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FOSS Network Infrastructure and Security/Security Functions with FOSS

Security Paradigms, Security Policies and Infrastructure Issues
Network and information security is one of the most important considerations when designing and deploying a network. Before we can get into the details of network security implementation with FOSS, we need to look at the different security paradigms that have been in existence for some time now. The older paradigm supported the notion that perimeter security was the ultimate form of security for any network. That myth has now been debunked, and the new paradigm advocates that every device must be made secure in itself in addition to the perimeter security imposed by firewalls and packet filters.

Security as a technical solution is also no longer a valid assumption. Security now involves not only stopping malicious packets from entering your network, but also preventing these malicious packets from coming from your network; deploying tools to detect intrusion attempts and generate logs; intelligent network sniffers and use of an individualized security policy; centralized logs to keep on top of information overload (or log overload), centrally managing the configuration firewalls and routers to detect changes (configuration management and security policy management); and host security tools to ensure that the last frontier of the protection – the host itself – is protecting data and is not compromised. All of these form a web of security that will effectively protect the organization, provided you know what you want to protect and how you want to protect it. This is to be articulated as a security policy.

The security policy is now one of the most important security tools for any organization as it helps in maintaining consistency in security implementation. Without the use of a security policy, it becomes difficult for an administrator to decide what to focus on. It also helps an organization to take action against people who defy the policy. In the absence of any such policy, work is always done on an ad hoc manner, which can create more possibilities for security breaches.

There is no one solution that can solve your security problems. What is more useful are best practices that document ways in which common security problems can be avoided. There are also security best practices for when a security breach occurs. Let’s look at common reasons for security breaches and some of the best practice remedies.

Open Architecture of TCP/IP
While TCP/IP is a highly efficient, cost-effective and flexible communications protocol for local and global communications, and is widely adopted on the global Internet and in the internal networks of large corporations, it was designed 20 years ago when the Internet consisted of a few hundred closely controlled hosts with limited security. The Internet now connects millions of computers that are controlled by millions of individuals and organizations, and where the core network is administered by thousands of competing operators. This complex network spans the whole globe, connected by fibres, leased lines, dial-up modems, and mobile phones. Thus, while it is tolerant of random errors, TCP/IP is vulnerable to a number of malicious attacks.

The basic premise of ‘end-to-end’ connectivity on the Internet means that you are as likely to receive illegitimate traffic as legitimate traffic. Thus the scope of security is not to stop all traffic, but to detect and deter the most malicious of attacks.

Common Types of Threats and Attacks

 * Unauthorized access – insecure hosts, cracking, intrusion
 * Eavesdropping on a transmission – gaining access to the medium to look for passwords, credit card numbers, or business secrets
 * Hijacking, or taking over a communication
 * Inspecting and modifying any data being transmitted
 * IP spoofing, or falsifying network addresses
 * Impersonating to fool access control mechanisms
 * Redirecting connections to a fake server
 * Denial of Service (DoS) attacks, when a huge amount of useless data coming to the target makes it unable to function properly
 * Interruption of service due to system destruction or using up all available system resources for the service CPU, memory, bandwidth
 * Default passwords and default configuration

Mistakes People Make that Lead to Security Breaches
Technological holes account for a great number of successful break-ins, but people do their share as well.

Five Worst Security Mistakes End-users Make

 * Failing to install an anti-virus, keep its signatures up-to-date, and perform full system scans regularly.
 * Opening unsolicited e-mail attachments without verifying their sources and checking their content first, or anything from untrusted sources.
 * Failing to install security patches, especially for frequently used software like those for word processing, web browser, e-mail client and operating systems.
 * Not making and testing backups.
 * Using a modem while connected through a local area network.

Seven Worst Security Mistakes Senior Executives Make

 * Assigning untrained people to maintain security and providing neither the training nor the time to make it possible to learn and do the job.
 * Failing to understand the relationship between information security and business problems. They understand physical security but do not see the consequences of poor information security.
 * Failing to deal with the operational aspects of security: making a few fixes and then not allowing the follow-through necessary to ensure that the problems stay fixed.
 * Relying primarily on a firewall.
 * Failing to realize how much money their information and organizational reputations are worth.
 * Authorizing reactive, short-term fixes so that problems re-emerge rapidly.
 * Pretending the problem will go away if they ignore it.

Ten Worst Security Mistakes IT People Make

 * Connecting systems to the Internet before hardening them.
 * Connecting test systems to the Internet with default accounts/passwords.
 * Failing to update systems when security holes are found.
 * Using telnet and other unencrypted protocols for managing systems, routers, firewalls and PKI.
 * Giving users passwords over the phone or changing user passwords in response to telephone or personal requests when the requester is not authenticated.
 * Failing to maintain and test backups.
 * Running unnecessary services: ftpd, telnetd, finger, rpc, mail, rservices.
 * Implementing firewalls with rules that do not stop malicious or dangerous traffic, whether incoming or outgoing.
 * Failing to implement or update virus detection software.
 * Failing to educate users on what to look for and what to do when they see a potential security problem.

Security Best Practices and To-dos
Some set a goal to fully and completely secure a system, which is impractical as it is usually impossible to make a system full-proof. A realistic goal is to set up a regular routine where you identify/correct as many vulnerabilities as possible.

Security Best Practices
A good security system makes it so difficult for an attacker to gain access that he gives up or gives an administrator enough time before he gets in. to secure it at least enough so that most intruders will not be able to break in, and will choose to direct their efforts elsewhere. This is just like putting iron bars and locks on our windows and doors. We do it not to ‘keep the robbers out’, but to persuade them to turn their attention to our neighbours. exploit, that Trojan virus, these mis-configurations), we focus our energies on tasks that provide the most comprehensive protection against the majority of threats. here to best fit their environment.
 * The idea is not that you should protect a system to the point that it cannot be compromised, but
 * Rather than directing our efforts at protecting against the thousands of specific threats (this
 * Best security practices are very dynamic, constantly changing and evolving.
 * Administrators should include their own best security practices and modify those mentioned

Points to Ponder

 * Take into consideration your needs, risks, and resources.
 * Information systems are unavoidably complex and fluid, so the most effective way to apply security is in layers.
 * You should place security measures at different points in your network, allowing each to do what it does best.
 * From an attacker’s perspective, you will have constructed a series of obstacles of varying difficulty between the attacker and your systems.
 * Secure each component in your system (firewalls, routers, servers, hosts and appliances) so that even if an attacker works his/her way through your obstacle course, at the end he/she will find systems that are resistant to attack.

Backup

 * Maintain full and reliable backups of all data and log files.
 * Archive all software (purchased or freeware), upgrades, and patches off-line so that they can be reloaded when necessary.
 * Backup configurations, such as the Windows registry and text/binary configuration files, used by the operating systems or applications.
 * Consider the media, retention requirements, storage, rotation, methods (incremental, differential, full) and scheduling.
 * Keep a copy of a full backup in a secure off-site location for disaster recovery.

Security To-dos

 * Enforce Deny by Default. Everything that is not allowed specifically is denied. This is a good way of tightening security.
 * Reduce access to things on a ‘need to know’ basis. That means that anybody who does not need access to a computer, a network, or a piece of information should not have access to it. This is also known as the Least Privilege Rule. Give the least privilege, the least access capabilities you can for someone to do his/her job.
 * Try to have identified choke points, which are points where you can inspect everything going on the network – i.e., a network where all communications pass through the Internet, a VPN concentrator where all the external accesses converge, a Modem pool where all external dial-in access come to, a dedicated VLAN where all the Wireless (WLAN) Access Points are connected to see who is coming from the wireless entry points.
 * Try to identify and focus on your weakest link, or the weakest part of your security that would compromise all the rest. Remember that the hacker just needs to succeed once to hack you, whereas you have to succeed all the time in your security job to protect your organization. So, the weakest link is always where you should focus your attention, trying to have no security ‘fence’ notably ‘lower’ than all the others in your network.
 * You should also try to have the capability to ‘fall back’ into a secure position in case of trouble. Security Policy Management systems can ensure the ‘lock down’ of the network in case of a worm, for example. Such a configuration would allow the DNS and maybe some vital traffic for the company (payroll, electronic fund transfer, ERP traffic) and block all the potential worm infection vectors (mail, web).
 * You should try to have a security device ‘deep down’ in your network, not only at the boundaries with the external world. If the life of your company depends on one computer holding sensitive data or running a factory, add a firewall in front of it. This is ‘Defense in Depth’.
 * If you diversify your defense, such as running two different brands of antivirus (one kind for your mail gateway, and another kind for the desktops and user machines), that may help you catch some attacks that were not blocked by one brand but will be by the other brand. You can also have a diversity of kinds of defense, like having antivirus and personal firewalls on the desktops.
 * KISS – Keep It Short and Simple. If your network and your security are simple, you will be less likely to have forgotten something that attackers will exploit. Clarity is important as you HAVE TO understand the whole network and the whole security organization. Do not feel that it is ‘dumb’ to ask ‘simple questions’; these are often the ones that will make everybody realize that there is a problem.
 * Security through obscurity is the opposite of the following principle. If someone tells you ‘do not worry, this is secure’ and does not want to explain the security mechanism, then YOU SHOULD WORRY. Hiding how things work and having your security depending on this to be secure is the worst thing you can have. For example, you should still secure computers in your network even if attackers cannot download the DNS zone of your company which lists the IP addresses. Sooner or later, an attacker will find a way to know about this ‘hidden’ computer and will then have full access. The only things you should keep secret and hidden are your password and your cryptographic keys (PGP private keys). Assume that all other knowledge may be known by attackers.

Firewalls
Many people think that a firewall is a single device that is configured to protect your internal network from the external world. In reality, a firewall is a system (or a group of systems) that enforces an access control policy between two networks. It disallows unauthorized and/or malicious traffic from traveling into and out of your network. Users must realize that firewalls cannot protect you from attacks that do not go through it. If there is another entry point to your network that is not protected by a firewall, then your network is not secure. Also, contrary to the common misconception, firewalls do not verify the content of the traffic going through it.

Types of Firewalls
Packet filtering firewalls
 * Examines the source and destination address of the data packet and either allows or denies the packet from traveling through the network.
 * Blocks access through the firewall to any packets that try to access ports which have been declared ‘off-limits’.

Application layer firewalls
 * Attempts to hide the configuration of the network behind the firewall by acting on behalf of the network/servers.
 * All requests for access are translated at the firewall so that all packets are sent to and from the firewall, rather than from the hosts behind the firewall.

Stateful inspection firewalls
 * Examines the state and the context of the packets.
 * Remembers what outgoing requests have been sent and allows only the responses to those requests back through the firewall.
 * Attempts to access the internal network that have not been requested by the internal network will be denied.

Firewall Best Practices
Regardless of which type of firewall, someone has to configure it to make it work properly. The rules for access must be defined and entered into the firewall for enforcement. A security manager is usually responsible for the firewall configuration. But again, if the policy is not made properly, then there is not much that the security manager can do. Some rules of thumb are: The default policy should be that if the firewall does not know what to do with the packet, it should deny/drop the data packet. Limit the number of applications that run on the firewall.
 * Explicitly deny all traffic except for what you want.
 * Do not rely only on your firewall for the protection of your network. Remember that it is only a device, and devices do fail.
 * Make sure you implement what is called ‘defense in depth’, or multiple layers of network protection.
 * Make sure all of the network traffic passes through the firewall.
 * If the firewall becomes disabled, then disable all communication.
 * If there is another way into the network (like a modem pool or a maintenance network connection), then this connection could be used to enter the network, completely bypassing firewall protection.
 * Disable or uninstall any unnecessary services and software on the firewall.
 * Consider running antivirus, content filtering, Virtual Private Network, etc. on different hardware.
 * Do not rely on packet filtering alone. Use stateful inspection and application proxies if possible.
 * Ensure that you are filtering packets for illegal/incorrect addresses, to avoid IP spoofing.
 * Ensure that physical access to the firewall is controlled.
 * Use firewalls internally to segment networks between different departments and permit access control based on business needs.
 * Remember that firewalls will not prevent attacks that originate from inside your network.

Netfilter/iptables
iptables13 is the most popular FOSS firewall tool available on GNU/Linux. It works in combination with netfilter, which is included as an integral part of the Linux kernel. It has been in the kernel as the firewalling subsystem since release 2.4.x.

iptables is a much improved version of previously available IP Chains and ipfwadm software.

It does packet filtering (stateless or stateful) as well as Network Address Translation (NAT) and IP Masquerading. It can also perform packet mangling (manipulation).

iptables consists of the following:
 * Userspace command for runtime configuration of the firewalling subsystem;
 * Kernel modules and the user interface application. Kernel modules are components that handle
 * various tasks and are compiled as loadable modules in the GNU/Linux kernel;
 * Generic table structure for the definition of rulesets; and
 * A number of classifiers (matches) and one connected action (target).

iptables – Tables, Chains and Rules iptables normally has multiple tables defined in the kernel. The default is the ‘filter’ table. The Linux kernel starts with three lists of rules in the ‘filter’ table. A chain is a checklist of rules. There are three built-in chains: the INPUT, OUTPUT and FORWARD chains. The Linux kernel examines each chain to decide the fate of the packet. In turn, each rule says ‘if the packet header looks like this, then here is what to do with the packet’.

iptables Syntax

Main iptables options

1. Create a new chain (-N).

2. Delete an empty chain (-X).

3. Change the policy for a built-in chain. (-P).

4. List the rules in a chain (-L).

5. Flush the rules out of a chain (-F).

6. Zero the packet and byte counters on all rules in a chain (-Z).

You can use ‘iptables –h’ to see a list of command options

To manipulate rules in a chain

1. Append a new rule to a chain (-A).

2. Insert a new rule at some position in a chain (-I).

3. Replace a rule at some position in a chain (-R).

4. Delete a rule at some position in a chain (-D).

5. Delete the first rule that matches in a chain (-D).

The default policies

The default policy is to accept all packets to, from, and through it.

INPUT ACCEPT any any FORWARD ACCEPT any any OUTPUT ACCEPT any any

To set the default policies to DROP all packets:

Targets – what to do if a packet matches a rule

ACCEPT DROP REJECT LOG

Example rules To get help:

Connection tracking

Stateful connection tracking of traversing packets with –m state –state options

NEW – packets that create a NEW connection ESTABLISHED – packets belonging to an existing connection – reply packets RELATED – packets related to an existing connection – ICMP error messages/ FTP data connections INVALID – packets not corresponding to any existing connection

 * # iptables –A FORWARD –d 192.0.2.0/24 –p tcp –m –state –state ESTABLISHED –j REJECT
 * # iptables –A FORWARD –m –state –state INVALID –j DROP

Sample iptables setup

Server Security, Host/Network Scanning and Intrusion Detection System
It is often advisable that a detection and prevention measure be run in addition to the firewall. This is commonly referred to as Network Scanning and Intrusion Detection System (IDS). There are also other proactive measures that can make your system and servers secure. Let’s look at some of these.

Server Security Dos and Don’ts

 * Run the server on a hardened and routinely updated operating system.
 * Keep current on software/application updates.
 * Ensure that you test these updates in a controlled, non-production environment whenever possible.
 * One server patch may undo a correction applied by a previous patch so scan the server after the patching-up.
 * Disable file sharing on all critical machines as it makes them vulnerable to information theft and certain types of quick-moving viruses.
 * Improper sharing configurations can expose critical system files or give full file system access to any hostile party.

Host/Network Scanning
Network scanning refers to the activity of scanning your own networks for vulnerabilities. There are tools available for this purpose. Incidentally, these are most often the same tools used by crackers and external parties to gauge your network security. Thus, using them yourself can lead you to quite a few of those security holes, which would go unnoticed otherwise. Below are some tips on what to scan for.

Scanning systems tips

 * Scans will help determine that only the required ports are open.
 * Check that services running on the open ports are not vulnerable to known security bugs/holes.
 * If new open ports are found, check if your systems have been compromised.
 * Perform full port scans using a tool like nmap/ndiff, nessus, or fscan on a regular basis.
 * Port scans should cover all ports (1-65,535), both UDP and TCP, on all systems: both client and server devices such as routers, switches, printers, and anything else connected (physically through wire or wireless) to your network.

Nmap
Nmap is a Network MAPper. It is a powerful utility for network exploration or security auditing, which can rapidly scan large networks or single hosts to determine the hosts available on the network, the services they (ports) are offering, the operating system (and OS version) they are running, and the type of packet filters/firewalls in use. It runs on most types of computers, and both console and graphical versions are available. It is also a GNU GPL software, available with full source code.

Here are examples of Nmap usage:

1. This option scans all reserved TCP ports on the machine. The -v means turn on verbose mode.

 * nmap -v target.example.com

2. This launches a stealth SYN scan against each machine that is up out of the 255 machines on class ´C´ where target.example.com resides. It also tries to determine what operating system is running on each host that is up and running. This requires root privileges because of the SYN scan and the OS detection.

 * nmap -sS -O target.example.com/24

3. This sends a Xmas tree scan to the first half of each of the 255 possible 8-bit subnets in the 198.116 class ´B´ address space. We are testing whether the systems run sshd, DNS, pop3d, mapd, or port 4564. Note that Xmas scan does not work on Microsoft boxes due to their reduced TCP stack. The same goes with CISCO, IRIX, HP/UX, and BSD boxes.

 * nmap -sX -p 22,53,110,143,4564 198.116.*.1-127

4. Rather than focus on a specific IP range, it is sometimes interesting to slice up the entire Internet and scan a small sample from each slice. This command finds all web servers on machines with IP addresses ending in .2.3, .2.4, or .2.5.

 * nmap -v —randomize_hosts -p 80 ´*.*.2.3-5´

5. Launch a stealth scan with OS detection on all privileged ports against 255 hosts in the network, and then output the results into the file /root/nmap.scan.

 * nmap –sS –O 192.0.2.0/24 –oN /root/nmap.scan

6. Launch a stealth scan with OS detection on specified ports against 255 hosts in the network, in verbose mode.

 * nmap –sS –O –v 192.0.2.0/24 –p ‘1-1024,1080,3128’</tt>

Nessus
The mantra for network monitoring and scanning could be: ‘Prevention is ideal, but detection is a must’. We must realize that the no prevention technique is fool-proof and new vulnerabilities are discovered every week that you may not be aware of. Thus, constant vigilance is required to detect new unknown attacks. Once you are attacked, without logs, you have little chance of finding what the attackers did. It is also common sense that you cannot detect an attack if you do not know what is occurring on your network. Logs provide the details of what is occurring, what systems are being attacked, and what systems have been compromised. If any log entry does not look right, you should investigate them immediately. But thousands of lines of logs are produced every day. It is necessary to use the appropriate tools to diagnose these. It is also necessary for these logs and scans to be compared against vulnerability databases, so that the security gap in the network can be known immediately.

Nessus
Nessus is a security scanner that can remotely audit a given network or server. It can determine whether ‘crackers’ may break into it, or misuse your network or servers in some way.

Unlike others, Nessus does not take anything for granted and will not assume that services run only on fixed ports. For example, if you run your web server on port 1234, Nessus will detect it and test its security. It will not make its security tests by the version number, but will really attempt to exploit the vulnerability. It is very fast and reliable, and has a modular architecture that allows you to fit it to your needs. Nessus also has front ends for both Windows and Macintosh.

Nessus Installation
Nessus is made up of two parts: a client and a server. You need a UNIX -like system to use the server. In this test, the standard client Nessus is used, mainly because it supports the cipher layer. The Nessus Security Scanner relies on the following items:
 * GTK - The Gimp Tool Kit, version 1.2
 * GTK is a set of Widgets (like Motif) which is used by many FOSS applications such as The Gimp.
 * GTK is used by the POSIX client Nessus.

 * Download it at ftp://ftp.gimp.org/pub/gtk/v1.2

 * Note #1: If your system comes with GTK, make sure that you have the gtk-config program installed.
 * If you do not, install the gtk-devel package that should come on your distribution CD-ROM.

 * Note #2: If you do not want to install GTK and/or if your system lacks X11, then you can compile a command-line client by doing.
 * <tt>/configure –disable-gtk</tt>
 * in nessus-core

 * Nmap, which we already covered earlier, is an excellent port scanner. It is available at http://www.insecure.org/nmap/.
 * OpenSSL (optional but heavily recommended) is used for the client-server communication as well as in the testing of SSL-enabled services. Get it at http://www.openssl.org.

Nessus also comes as a standalone package that auto-installs itself. To use it, download the script nessusinstaller. sh at http://www.nessus.org/download.html.

Using Nessus
Create a nessusd account

The nessusd server has its own user database, with each user having a set of restrictions. This allows you to share a single nessusd server for a whole network and different administrators who will only test their part of the network.

The utility nessus-adduser takes care of the creation of a new account:

 * <tt># nessus-adduser</tt>

Using /var/tmp as a temporary file holder

Add a new nessusd user

 * Login: sunil
 * Authentication (pass/cert) [pass]:
 * Login password: nessus
 * User rules

nessusd has a rules system which allows you to restrict the hosts that Sunil has the right to test. For instance, you may want him to be able to scan his own host only.

Please see the nessus-adduser man page for the rules syntax. Enter the rules for this user, and hit ctrl-D once you are done: (the user can have an empty rules set)

 * Login: sunil
 * Password: nessus
 * DN:
 * Rules:

 * Is that ok? (y/n) [y]
 * User added.

Configure your Nessus daemon

In the file /usr/local/etc/nessus/nessusd.conf, you can set several options for nessusd. Typically, this is where you can define that you want nessusd to use your favourite language. The standard configuration file has been kept for this illustration.

Start nessusd

Once all of this is done, you can safely start nessusd as root:

 * <tt>nessusd -D</tt>

Fire up Nessus in X windows graphical environment

Click on Login, since this setup is correct. Since this is the first time you are connecting to this server, it will ask for the password. The next time you connect to it, the public key will be enough. Once connected, the Log-in button changes to Log-out, and a Connected label appears at its left.

The security checks configuration

Let all the security checks be performed, except the DoS attacks, because you do not want hosts to crash.

Clicking on a plugin name will pop up a window explaining what the plugin does.

The plugins preferences

Some security checks will require extra arguments. For instance, the pop2 overflow security test needs a valid pop account. The plugin, which tests whether an FTP directory is writeable or not, asks if it should just trust the permissions or really attempt to store a file.

The scan options

Here you choose which port scanner you want to use. Opt for the Nmap tcp connect scanner, since it is the fastest.

Define the targets

Uncheck the ‘Perform a DNS transfer zone’ option, since it would make DNS transfer on fr.nessus.org and nessus.org, and it would be useless, since it would not gain any new hosts.

Use the following options to define the targets:

 * 192.0.2.1 A single IP address.
 * 192.0.2.1-7 A range of IP addresses.
 * 192.0.2.1-192.0.3.50 Another range of IP addresses.
 * 192.0.2.1/29 Again a range of IP addresses in CIDR
 * prof.fr.nessus.org A hostname in FQDN notation.
 * prof A hostname (as long as it is resolvable on the server).

 * prof, 192.0.2.1/29, ... Any combination of the above mentioned forms separated by a comma.

The rules section

The rules allow a user to restrict his test. For instance, if you want to test 192.0.2.0/29, except 192.0.2.2. The rule set entered allows you to do that. Once all of this is done, start the scan.

The Nessus scan report

Now that the scan is over, the report window just pops up.

Resolving the security issues

Go through the scan report and try to resolve reported security holes on the respective servers by following the suggestions given in the report OR by referring to the vendor’s site.

Intrusion Detection System (IDS)
Intrusion detection is the art of detecting inappropriate, incorrect, or anomalous activity. IDS inspects/ sniffs all network traffic passing through it for any abnormal content. It has a built-in signature-base and anomaly detection, which provides the capability to look for set ‘patterns’ in packets. It can also string search signature (i.e., look for confidential information), log and TCP reset features. IDS provides worthwhile information about malicious network traffic and helps identify the source of incoming probes, scans, or attacks. It is similar to a security camera or a burglar alarm as it alerts security personnel that someone is picking the ‘lock’ – i.e., it alerts security personnel that a network invasion may be in progress.

SNORT
The most common FOSS IDS in use is SNORT.19 It does the following:
 * Monitors network traffic for predefined suspicious activities or patterns
 * Alerts system administrators when potential hostile traffic is detected
 * Serves as a cross-platform, lightweight network intrusion detection tool
 * Can be deployed to monitor small TCP/IP networks
 * Detects a wide variety of suspicious network traffic as well as outright attacks
 * Deployed rapidly to fill potential holes in a network’s security coverage

Three Modes of SNORT
Sniffer mode

Displays the packet headers or data

Packet logger mode

Records packets to the disk

 * log all packets in binary mode
 * log to display packets in ascii mode from the binary log
 * log to display packets in ascii mode from the binary log

Network intrusion detection mode

Does not record every single packet sent down the wire

 * <tt>snort -d -h 192.0.2.0/24 -l ./log -c snort.conf</tt>

This will configure SNORT to run in its most basic NIDS mode, logging packets that the rules tell it to in plain ASCII to a hierarchical directory structure (just like the packet logger mode).

To send NIDS alerts to syslog use -s:

 * <tt>snort -s -h 192.0.2.0/24 –l ./log -c snort.conf</tt>

High Performance Configuration

This logs packets in tcpdump format and produces minimal alerts.

To read this file back and break out the data in the familiar SNORT format:

To run SNORT in daemon mode (provide full paths):

usr/local/bin/snort -d -h 192.0.2.0/24 -l /var/log/snortlogs -c / usr/local/etc/snort.conf -s -D

To post packet logs to public mailing lists use –O to obfuscate your IP addresses

 * <tt>snort -d -v -r snort.log -O -h 192.0.2.0/24</tt>

To get help options:

 * <tt>snort –h</tt>

References

http://www.snort.org/docs/writing_rules/

http://www.snort.org/docs/lisapaper.txt

OpenSSH
One of the biggest advantages of UNIX and GNU/Linux is the ability to work remotely on the server systems. This feature is an inherent part of any UNIX-like operating system. In earlier days, most people used Telnet to log remotely into servers but now Telnet has been made obsolete by ssh or secure shell.

The main difference between Telnet and ssh is the secure communication protocol of the latter. In Telnet all of the communication was done in plain text, whereas in ssh all communication is encrypted.

OpenSSH is both an ssh server and client. It is installed by default on most GNU/Linux distributions. Since it even encrypts the password sent to set up the session, it effectively eliminates eavesdropping, connection hijacking, and other network-level attacks. It includes the following different server subsystems:

sshd – ssh daemon run on the server machine sftp-server – sftp server sub-system ssh-agent – authentication agent that holds the keys ssh-add – used to register new keys with the Agent ssh-keygen – used to create public authentication keys

OpenSSH Config Files
Since OpenSSH is both a client and a server, there are two configuration files for each purpose:

/etc/ssh/ssh_config – ssh client systemwide configuration file, provides defaults for users

/etc/ssh/sshd_config - sshd server system-wide configuration file

OpenSSH Server Configuration
Installation and basic operation

Install the openssh-server and openssh rpm package included in your Linux distribution. Most GNU/ Linux distributions will have the option to install OpenSSH. Please note that the openssh-server package depends on the openssh package. OpenSSH packages also require the OpenSSL package (openssl) which installs several important cryptographic libraries that help OpenSSH provide encrypted communications.

OpenSSH daemon, sshd, uses the configuration file ‘/etc/ssh/sshd_config’

The default config file is sufficient. For customization, refer to the sshd main page for config options.

Editing/viewing the sshd_config file

[root@mail /] # vi /etc/ssh/sshd_config

 * <tt>#Port 22 - Specifies the port number that sshd listens on</tt>
 * <tt>#Protocol 2,1 - Specifies the protocol versions sshd supports</tt>
 * <tt>#ListenAddress 0.0.0.0 - Specifies the local addresses sshd should listen on</tt>
 * <tt>#HostKey /etc/ssh/ssh_host_rsa_key - Specifies a file containing a private host key used by SSH</tt>
 * <tt>#SyslogFacility AUTH - Gives the facility code that is used when sshd logs messages</tt>
 * <tt>#LogLevel INFO - Gives the verbosity level that is used when sshd logs messages</tt>
 * <tt>#LoginGraceTime 600 – time limit for a user to log in</tt>
 * <tt>#PermitRootLogin yes - Specifies whether the root can login using ssh</tt>
 * <tt>#StrictModes yes - Specifies whether sshd should check file modes and ownership of the user’s files and home directory before accepting login</tt>
 * <tt>#PubkeyAuthentication yes - Specifies whether public key authentication is allowed</tt>
 * <tt>#PasswordAuthentication yes - Specifies whether password authentication is allowed</tt>
 * <tt>#PermitEmptyPasswords no - When password authentication is allowed, it specifies whether the server allows login to accounts with empty password strings</tt>
 * <tt>#MaxStartups 10 - Specifies the maximum number of concurrent unauthenticated connections to the sshd daemon</tt>
 * <tt>#KeepAlive yes - Specifies whether the system should send TCP keepalive messages to the other side</tt>
 * <tt>#VerifyReverseMapping no - Specifies whether sshd should try to verify the remote host name</tt>
 * <tt>Subsystem sftp /usr/libexec/opensshsftp-server</tt>

Managing the sshd service

To start the service: <tt>#/etc/rc.d/init.d/ sshd start</tt>

To stop the service: <tt>#/etc/rc.d/init.d/ sshd stop</tt>

To restart the service: <tt>#/etc/rc.d/init.d/ sshd restart</tt>

To automatically run the service: <tt># chkconfig sshd on</tt>

OpenSSH Client Configuration
To connect to an OpenSSH server from a client machine, you must have the openssh-clients and openssh packages installed on the client machine.

System-wide ssh client configuration is stored in /etc/ssh_config and is used as the default for all systemwide users.

The configuration values can be changed in per user configuration files or on the command line. The default home directory is ~/.ssh

Using the ssh with password authentication

1. Make sure you have the following enabled in /etc/sshd_config file on the ssh server

PasswordAuthentication yes

2. To log in to a host named server.com, type the following:

$ ssh gaurab@server.com

The first time you ssh to a remote machine, you will see a message similar to the following:

The authenticity of host ‘server.com (192.0.2.22)’ can’t be established. RSA key fingerprint is 0f:41:6c:52:31:59:43:0f:dd:49:5f:3d:47:9d:b5:9e. Are you sure you want to continue connecting (yes/no)? yes

Type yes to continue. This will add the server to your list of known hosts as seen in the following message:

Warning: Permanently added ‘server.com,192.0.2.22’ (RSA) to the list of knownhosts. gaurab@server.com’s password: Last login: Sat Oct 16 19:34:13 2004 from gw-ktm.lahai.com [gaurab@server.com gaurab]$

3. known_hosts file in .ssh folder contains the remote servers’ host keys:

$ more known_hosts server.com,192.0.2.22 ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEA5IwKqHiqSeXjrX3dCpS1gXZo9GqJ0hkk+clf+WmABYbEH6IGMyy2CeA RtaR6QLpqB1SaGEFsn84dqA6kWLYfn4FuDVDc8KTyABLVEMOm6NnLZkHPKr3Cb0RgivDYSYHlwgWu Di7XBvmoC44WA2EbM7eBy5h1kHrXZ5yPXq3rxI0=

Using the ssh command with public key authentication

1. Make sure you have the following enabled in /etc/sshd_config file on the ssh server.

PubkeyAuthentication yes

2. Key pair generation: ssh-keygen - authentication key generation, management and conversion

To generate a RSA key pair to work with version 2 of the protocol:

$ ssh-keygen -t rsa

Generating public/private rsa key pair. Enter the file in which to save the key (/home/gaurab/.ssh/id_rsa):

Enter a passphrase that is different from your account password and confirm it by entering it again: Enter passphrase (empty for no passphrase): Enter same passphrase again:

Your identification has been saved in /home/gaurab/.ssh/id_rsa. Your public key has been saved in /home/gaurab/.ssh/id_rsa.pub. The key fingerprint is: e5:a1:ac:ce:8d:16:3a:b9:3a:e4:e9:06:9c:90:b6:da gaurab@lahai.com

The public key is written to ~/.ssh/id_rsa.pub. The private key is written to ~/.ssh/id_rsa. Never distribute your private key to anyone and change the permissions of your .ssh directory using the command chmod 755 ~/.ssh

$ ll .ssh/ total 8 -rw——— 1 gaurab gaurab 951 Oct 16 19:37 id_rsa -rw-r—r— 1 gaurab gaurab 236 Oct 16 19:37 id_rsa.pub

Copy the contents of ~/.ssh/id_rsa.pub to ~/.ssh/authorized_keys on the machine to which you want to connect.

If the file ~/.ssh/authorized_keys does not exist, you can copy the file ~/.ssh/id_rsa.pub to the file ~/.ssh/authorized_keys on the remote SSH server.

Securely copy your public key file to the remote ssh server:

$ scp ~/.ssh/id_rsa.pub gaurab@server.com:

Logon to the remote ssh server using password authentication, one more time:

$ ssh gaurab@server.com

Copy the content of the public key file to authorized_keys file on the remote host:

$ cat id_rsa.pub >> ~/.ssh/authorized_keys

Now, logon to the remote ssh server via public key authentication:

$ ssh gaurab@server.com Enter passphrase for key ‘/home/gaurab/.ssh/id_rsa’: Last login: Sat Oct 16 19:40:11 2004 from myhost.com [gaurab@server.com gaurab]$

To run a command on the remote host with ssh and exit:

$ ssh ns.lahai.com ls /usr/share/doc

Using the scp command

The scp command is used to transfer files between machines over a secure, encrypted connection.

To transfer the local file shadowman to /home/username/shadowman on penguin.example.net:

$ scp shadowman username@penguin.example.net:/home/username

To transfer a remote file to the local system:

$ scp username@tohostname:/remotefile /newlocalfile

To transfer the contents of the directory /downloads to an existing directory called “uploads” on the remote machine penguin.example.net:

$ scp /downloads/* username@penguin.example.net:/uploads/

Using the sftp command

The sftp command is used to open a secure, interactive FTP session via an encrypted channel.

$ sftp username@hostname.com

Once authenticated, you can use a set of commands similar to using FTP.


text:
User:Theanphibian

My profile

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: User:Theanphibian


text:
File talk:European History.pdf

can no download file. everything seems to be working (status 200) but the downloaded file has a size of 0 Byte. first thought could be my fault, so i tried to download the file on a remote server. that's what wget told me:

--08:13:58-- http://upload.wikimedia.org/wikibooks/en/3/38/European_History.pdf => `European_History.pdf' Resolving upload.wikimedia.org... 145.97.39.156 Connecting to upload.wikimedia.org|145.97.39.156|:80... connected. HTTP request sent, awaiting response... 200 OK Length: 0 [application/pdf] [ <=>                                                                                ] 0             --.--K/s 08:14:04 (0.00 B/s) - `European_History.pdf' saved [0/0]

Thanks. --80.64.186.97 06:20, 30 May 2007 (UTC)

 * The problem may be local to your computer or ISP. I just downloaded this file without problem. Webaware talk 02:16, 3 June 2007 (UTC)

 * Working fine now. But it was neither caused by my ISP nor my computer, since I tried it on two different computers with different ISPs. --80.64.186.97 20:24, 3 June 2007 (UTC)

title: File talk:European History.pdf


text:
WebObjects/Web Applications/Deployment/FreeBSD 6.x WO 5.3.3 port

FreeBSD 6.x - WO 5.3.3 - Quinton Dolan The WebObjects Deployment port allows you to automatically install the webobjects runtime as well as a variety of WebObjects related dependencies. These include WOAdaptors for Apache and CGI/FastCGI, JDBC & EOF plugins (for FrontBase, PostgreSQL, MySQL & OpenBase), Project Wonder and WOProject. http://wiki.objectstyle.org/confluence/display/WO/WebObjects+5.3.3+Deployment+on+FreeBSD+6.x


text:
SwisTrack/Components/BlobDetectionMinMax

Description
This component detects the blobs resulting of a thresholding step and keeps those with their area, orientation and compactness between specified bondaries. A maximum number of object can be selected, and in this case, only the biggest objects will be kept.

Input

A binary (black and white) image.

Output

Particles.

Max. blobs
Maximum number of blobs kept. Only the biggest blobs are selected.

Area Selection
Choose if a selection based on the blobs area is done.

Min. blob size
Minimal area of a selected blob in pixels.

Max. blob size
Maximal area of a selected blob in pixels.

Compactness Selection
Choose if a selection based on the blobs compactness is done.

Min. compactness
Minimal compactness of a selected blob (between 0 and 1).

Max. compactness
Maximal compactness of a selected blob (between 0 and 1).

Orientation Selection
Choose if a selection based on the blobs orientation is done.

Min. orientation
Minimal orientation of a selected blob in degrees.

Max. orientation
Maximal orientation of a selected blob in degrees.


text:
Usenet Explorer User's Manual/Appendixes

=Appendixes=

../Versions/
1.9, 1.8, 1.7, ...

../Glossary/
../Glossary/,

../Index/
A, B, C, T,

../References/
Tutorials, Forums


text:
Usenet Explorer User's Manual/User Interface

This chapter explains the user interface of Usenet Explorer.

/Icons/
Elements of Icons, Workspace Icons, Newsgroup Icons

Windows and Panes
Workspace, /Task Manager/

/Toolbars/
Quick Filter bar, Search Service bar, Status bar

Editors
Filter editor, Properties

/Keyboard Shortcuts/
TODO,

/Workspace/
TODO,

/Task Manager/
TODO,

/Quick Filter Bar/
TODO,

/Search Service Bar/
TODO,

/Toolbar/
TODO,

/Status Bar/
TODO,


text:
Usenet Explorer User's Manual/Appendixes/Versions

= Versions =


text:
Usenet Explorer User's Manual/Glossary

= Glossary =

title: Usenet Explorer User's Manual/Glossary


text:
Usenet Explorer User's Manual/Index

= Index =

F
Forums

T
Tutorials

title: Usenet Explorer User's Manual/Index


text:
Usenet Explorer User's Manual/References

Websites

 * Usenet Explorer official home page The official home page.

Tutorials

 * Usenet Explorer A tutorial in Dutch by Harry Vos.
 * Handleiding: Downloaden met Usenet Explorer A tutorial in Dutch by Jaapf.
 * Tutorial: Downloading with Usenet Explorer A tutorial in English by Jaapf.

Forums

 * Usenet Explorer The "official" forum (in English).
 * Usenet Explorer A forum in French.


text:
Usenet Explorer User's Manual/Manual/Quick Start

= Quick Start =
 * 1) download Usenet Explorer
 * 2) unpack
 * 3) add news servers
 * 4) add newsgroups
 * 5) download headers
 * 6) download messages
 * 7) save attachments
 * 8) check attachments
 * Get and install QuickPar.
 * 1) unpack attachments
 * Get and install WinRAR.


text:
Usenet Explorer User's Manual/Manual/Installation

This chapter guides you through the installation of Usenet Explorer.

Download
Download Usenet Explorer from the Download page on the Usenet Explorer site.

Create Database
TODO: what's the "best" location for the Usenet Explorer database (how to get there conveniently with windows explorer, ...)

where to go from here
Once you have installed Usenet Explorer, go to the ../Configuration/ section.


text:
FOSS Network Infrastructure and Security/Network Planning

A network in any computing environment is always a long-term investment. It is imperative that proper planning be done before going all out to deploy a network. A few pointers on network design and development are given below.

Network Planning Basics
Capacity: Plan for at least two to three years

Infrastructure: Build for at least one year

Business Models: Look after the next quarter

As illustrated above, there are three factors to consider when planning a network. The first is capacity, both in terms of bandwidth as well as human resource. Second, you need to consider the infrastructure that you need to build to support the capacity. Ultimately, your network is good only for as long as it can help you meet business needs and costs. For both service providers and non-profit organizations, planning should be for at least two to three years. However, at the same time, the infrastructure should be able to handle at least another year of operation.

Major Considerations
Here are some more points to consider:

 * Identify the components of a LAN/WAN and determine the type of network design that is most appropriate for a given site.
 * Identify the different media used in network communications, distinguish between them, and determine how to use them to connect servers and workstations in a network.
 * Differentiate between the different networking standards, protocols, and access methods, and determine which would be most appropriate for a given situation.
 * Recognize the primary network architectures, identify their major characteristics, and determine which would be most appropriate for a proposed system.
 * Identify the primary functions of network operating systems and distinguish between a centralized computing environment and a client/server environment.
 * Determine how to implement and support the major networking components (including the server, operating system and clients), and propose a system for adequately securing data on a given LAN and protecting the system’s components.
 * Distinguish between LANs and WANs, identify the components used to expand a LAN into a WAN, and determine how to implement an appropriate modem in the larger LAN/WAN environment.
 * Identify strategic LAN support tools and resources, and determine how to use these in troubleshooting basic network problems.

Services Planning
Mail

Choose a reliable MTA, but at the same time be cautious about spam, as it is a big headache.

Make redundant servers.

Separate user servers from real servers.

DNS

Use the latest BIND releases.

Plan nomenclature properly, but do not make it too obvious.

Redundancy is most important.

Arrange to host alternative DNS servers at off site/multiple locations.

User Services

E-mail access – POP, Web.

Web access.

Transparent caching/proxy.

Core Services – Infrastructure

Multi home: try to buy bandwidth from an IX facility.

Buying capacity is cheaper than managed capacity.

Plan to peer with other ISPs as much as possible.

Routers

Use loopback address in a separate subnet.

Use the lookback address as RouterID.

For core routers, memory is important.

For edge routers, ports are important.

Take configuration backups regularly.

Switching

Switching capacity is never enough. Invest in large switches, if that is what you will need in future.

Use VLANs to separate different groups of machines/networks.

For backbones, gigabit Ethernet is now more commonly used.

Backbone

Switched vs. routed backbone.

The same decisions apply as in LAN connections.

The backbone itself can be switched, and the traffic between different subnets can be routed.

Switching has its advantages if there is large local broadband use.

Branch Offices

Branch offices (BOs) need to be planned well in advance.

BOs tend to grow faster than you think they will.

 * Basic considerations for BOs.
 * Multihoming.
 * Distributed user services.
 * Authentication/remote management.

Hosts

Core services.

Use separate servers for separate functions.

1U servers are more manageable and also consume less power and space.

Use standardized platform as much as possible.

Using FOSS
In an integrated environment, FOSS tools are used alongside proprietary software and tools. This is a common scenario, but when it comes to network infrastructure, resources and security, FOSS provides an established and proven track record as the best software choice available in this area. In a networked environment, the ability to quickly diagnose and solve problems is critical. Experienced network administrators know that 80 percent of all network-related problems have to do with cabling and physical problems. Many problems can be minimized by using the best software in each category and, today, as argued above, the best software in most cases are FOSS.


text:
Talk:Ethnomedicine/Home Remedies

this already appears under the "Toothpaste" category.

title: Talk:Ethnomedicine/Home Remedies


text:
Korean/Nouns

''This lesson is incomplete. Help complete it by reading the talk page or by clicking "edit".''

Korean nouns (명사):
 * Common nouns (보통 명사)
 * Proper nouns (고유 명사)
 * Dependent nouns (의존 명사)

Honorifics
시 and 으시

title: Korean/Nouns


text:
FOSS Network Infrastructure and Security/Further References

The most useful resource for further reading is the Internet. Here are some useful sites on the Internet.

General reading/references
a. Free Software Foundation

b. IOSN

c. Linux Documentation Project ,

d. Internet Standards and RFCs

e. Internet Society / NSRC Workshop Resources

f. Network Startup Resource Center

g. UNESCO Free Software Portal

h. Networking and Information Technology Observatory  - click on the “open source” theme.

Linux software download and documentation
a. Source Forge

b. Kernel .org

c. Freshmeat

d. RPMFind

e. DNS/BIND

f. Sendmail

g. SSL

h. SSH <http://www.openssh.org>

Security-related sites
a. Security Focus <http://www.securityfocus.com>

b. CERT <http://www.cert.org>

Forums
a. Slashdot <http://www.slashdot.org>

b. Linux Online <http://www..linux.com>

Events
a. APRICOT <http://www.apricot.net>

b. NANOG <http://www.nanog.org>

c. AfNOG <http://www.afnog.org>

d. SANOG <http://www.sanog.org>

e. O’Reilly Open Source Conference <http://www.oreilly.com>

Useful mailing lists
a. ISP-Linux <http://www.isp-linux.com>

b. NANOG <http://www.nanog.org>

c. AfNOG <http://www.afnog.org>

d. SANOG <http://www.sanog.org>

e. NSP Security Mailing List <http://puck.nether.net/nsp-sec>

List of FOSS most commonly used by ISPs
Operating system

Debian Linux <http://www.debian.org>

FreeBSD <http://www.freebsd.org>

Accounting authorization authentication

Cistron Radius <http://www.radius.cistron.nl>

FreeRadius <http://www.freeradius.org>

Freeside <http://www.sisd.com/freeside>

Domain Name Server

BIND <http://www.isc.org/products/BIND>

MAIL servers and related software

Sendmail <http://www.sendmail.org>

Exim <http://www.exim.org>

CourierImap <http://www.inter7.com/courierimap>

SpamAssassin <http://www.spamassassin.org>

Majordomo <http://www.greatcircle.com/majordomo>

Web -related software

Apache <http://www.apache.org>

PHP <http://www.php.net>

Proxy and caching servers

Squid <http://www.squid-cache.org>

Security-related

Iptables <http://www.netfilter.org>

Snort <http://www.snort.org>

OpenSSH <http://www.openssh.org>

OpenSSL <http://www.openssl.org>

Network management system

MRTG <http://www.mrtg.org>

Netsaint <http://www.netsaint.org>

Nmap <http://www.nmap.org>

Ntop <http://www.ntop.org>

Browsers and e-mail clients

Firefox Internet Browser <http://www.firefox.com>

Mozilla <http://www.mozilla.org>

Thunderbird E-mail Client <http://www.firefox.com>

Books
Linux Books tends to get obsolete very quickly. But they are still a handy reference, when your access to the Internet is limited.

O’Reilly Books
Practical Internet and UNIX Security

Linux in a Nut Shell

Building Secure Servers with Linux

DNS and BIND

Essential System Administration

Linux Security Cookbook

Network Troubleshooting Tools

Other O’Reilly books on FOSS are also highly recommended.

Other Books
Unix Unleashed. System Administrator’s Edition. India: Techmedia.

Special Edition - Using Linux. 3rd Edition. India: Prentice Hall of India Ltd.

Tanenbum, A. Computer Networks. Prentice Hall.

Free BSD References
The FreeBSD handbook is a full guide on FreeBSD.

http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/

http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/network-communication.html

http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/advanced-networking.html


text: FOSS Network Infrastructure and Security/Glossary


text:
FOSS Network Infrastructure and Security/About the Author

Gaurab Raj Upadhaya is currently employed as Internet Economics Analyst/Staff Engineer at Packet Clearing House (http://www.pch.net), a research non-profit based in Berkeley, California. He works mostly in Internet backbone operations, analyzing peering relationships between operators and roles of Internet Exchange Points in different parts of Asia. Much of the work involves training ISPs in developing countries about best practices on network operations. He also runs the PCH INOC-DBA (http://www.pch.net/inocdba) hotline phone system for service providers. He initiated the Nepal Internet Exchange and currently serves as its voluntary CEO.

In 2003, Gaurab started the South Asian Network Operators Group (SANOG), a non-profit educational event and forum for ISPs in the South Asian Region (http://www.sanog.org). SANOG has a track dedicated to in-depth hands-on workshops on ISP operations using FOSS, along side other workshops on BIND/DNS and Security. He currently chairs SANOG. He is also the vice-chair of Asia Pacific Internet Association (http://www.apia.org), and Management Committee member for Asia Pacific Regional Internet Conference on Operational Technologies (APRICOT) (http://www.apricot.net).

In the past he has served as a National UN Volunteer, working for the UNDP/Cisco/USAID Least Developing Countries Initiative (http://www.cisco.com/edu/ldci) as Unites volunteer (http://www.unites.org). He has been using Linux and FOSS since 1996. He previously worked as system and network administrator for United Mission to Nepal (http://www.umn.org.np).

His personal website is http://www.gaurab.org.np. He likes travel, photography and reading books when he is not on the network.


text:
FOSS Network Infrastructure and Security/Acknowledgements

I would like to acknowledge all those who have helped and contributed to the preparation of this e-primer. My colleagues at PCH, Bill Woodcock and Daniel S. Silverstein, have provided both structural and content inputs. Ritesh Raj Josti of Mercantile Communications, who is my co-instructor at APRICOT, has provided the basis for a lot of security-related materials.

Thanks to Bill Manning (EP.net) for reviewing DNS-related materials and Merike Kaeo (Doubleshot Security) for reviewing the security-related materials. Vicky Shrestha (WorldlinkCommunications) for doing a sanity checks on all the configurations.

I’d also like to thank the IOSN Team, Kenneth Wong, Sunil Abraham, Khairil Yusof, Phet Sayo and Shahid Akhtar, for being patient.

Lastly, thanks to all the reviewers – Philippe Langlois, Dinesh Nair, Devdas Bhagat, Nah Soo Hoe, Raj Mathur, Satyakam Goswami, Vimal Joseph and Simos Xenitellis.


text:
FOSS Network Infrastructure and Security/About APDIP

The Asia-Pacific Development Information Programme (APDIP) is an initiative of the United Nations Development Programme (UNDP) that aims to promote the development and application of information and communication technologies for sustainable human development in the Asia- Pacific region. APDIP aims to meet its goals by focusing on three inter-related core areas: (i) policy development and dialogue; (ii) access; and (iii) content development and knowledge management.

APDIP collaborates with national governments, regional, international and multi-lateral development organizations, UN agencies, educational and research organizations, civil society groups, and the private sector in integrating ICTs in the development process. It does so by employing a dynamic mix of strategies – awareness raising, capacity building, technical assistance and advice, research and development, knowledge sharing and partnership building.

http://www.apdip.net


text:
FOSS Network Infrastructure and Security/About IOSN

The International Open Source Network (IOSN) is an initiative of APDIP and supported by the International Development Research Centre of Canada. IOSN is a Centre of Excellence for Free/Open Source Software (FOSS), Open Content and Open Standards in the Asia-Pacific region. It is a network with a small secretariat based at the UNDP Regional Centre in Bangkok and three centres of excellence – IOSN ASEAN+3, IOSN PIC (Pacific Island Countries), and IOSN South Asia, based in Manila, Suva and Chennai respectively.

IOSN provides policy and technical advice on FOSS to governments, civil society and the private sector. It produces FOSS awareness and training materials and distributes them under open content licenses. It also organizes awareness raising, training, research and networking initiatives to assist countries in developing a pool of human resources skilled in the use and development of FOSS. IOSN works primarily through its web portal http://www.iosn.net that is collectively managed by the FOSS community. The web portal serves as a clearinghouse and a platform for knowledge sharing and collaborations.

http://www.iosn.net


text:
User talk:Suncoaster

Copyright problem with Image:Goodside2.jpg
Webaware talk 08:50, 30 May 2007 (UTC)

title: User talk:Suncoaster


text:
Talk:Mac OS X Tiger/Meet the Applications/Safari

Just starting.

Spelling
Anyone know a way to make the "check as you type" check stick so that underlining sticks after you relaunch Safari? Can't find any ref on the internet on this.--70.41.146.174 09:03, 30 May 2007 (UTC)
 * quick pop in to say I created my account so I can follow up on stuff now....--Smkolins 14:23, 30 May 2007 (UTC)


text:
User talk:DarthBob~enwikibooks

Hi Darthbob - I noticed you added the spell checking section of Safari - if you are still around I wondered if you had some thoughts about spell checking in Safari - see Talk:Mac OS X Tiger/Meet the Applications/Safari. Just popped in here for something ... might have to stick around and make myself an account!--70.41.146.174 09:06, 30 May 2007 (UTC)

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

Unfortunately, your account clashes with another account also called DarthBob. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name DarthBob~enwikibooks that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:08, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 04:51, 19 April 2015 (UTC)

title: User talk:DarthBob~enwikibooks


text:
Wikijunior:Human Body/Blood Vessels

Blood vessels are tiny tubes inside your body that carry blood around your body.

What do blood vessels look like?
Blood vessels are long thin tubes that run all through the body. Some are larger than others. Most are very small. Some are so small that you can't even see them without a microscope. If you look at your wrist or leg, you can see blue lines just below the skin. These are your blood vessels. They look blue because of the way light goes through your skin and lights up the carbon dioxide rich cells in the blood stream, but the blood plasma remains red. Oxygenated blood is bright red because of the hemoglobin, deoxygenated blood is actually dark red but looks blue.

There are a huge number of blood vessels in your body. If they were all stretched out, there would be over 60,000 miles of blood vessels!

What are the parts of the blood vessels?
Blood vessels are hollow tubes that blood flows through. They have walls made of muscle. The hollow place inside of the blood vessel is called the lumen.

Veins have small flaps of tissue called valves. These keep the blood flowing the right direction by closing if any blood tries to flow backwards. Without these, our blood would be flowing in every direction possible.

What is the function of the blood vessels?

The main function of blood vessels is to carry blood through the body. The blood carries oxygen, nutrients, and wastes that need to circulate the body. The three kinds of blood vessels are: arteries, veins, and capillaries.

The arteries carry blood away from the heart and transport it to the rest of the body. The blood in arteries carries oxygen and nutrients to different parts of the body.(with the exception of pulmonary artery). They have valves to ensure that the blood flows only in one direction. The veins carry blood the opposite direction, back to the heart from the rest of the body. The blood in veins carry wastes that need to leave the body.(with the exception of pulmonary vein)

Arteries have a thicker wall and a smaller inside hole than veins. The reason for this is that arteries carry blood that is pumped all over the body. That pumping requires a lot of power from the heart. This pumping causes high pressure, and so the walls of the artery need to be thick and strong.

The third kind of blood vessels is capillaries. They are very tiny. You would need a microscope to see one. They connect the arteries to the veins. They let oxygen and nutrients pass from the blood to body cells. They also let carbon dioxide and other wastes pass from the cells back into the blood. This is possible because the walls of the capillaries are so thin that substances can pass through easily. This happens through a process called diffusion.The capillaries are the smallest vessels have walls which are one - cell thick.

How do the blood vessels interact with other parts of the body?
Blood vessels start at the heart and extend out to the rest of the body. The heart is important in pumping the blood through the blood vessels. The stomach and small intestine are where the blood picks up nutrients.

Blood vessels touch almost every part of the body. They carry oxygen and nutrients to every other organ. Without blood vessels, the rest of our body couldn't survive, because there is no part of the body to carry the nutrients.

How can you keep your blood vessels healthy?
An important part of keeping your blood vessels healthy is eating right.

You may have heard of cholesterol. If you eat too much fatty food, like butter, cheese, chips, or crisps, some of this fat naturally builds up around the arteries and veins. This is known as cholesterol. If there is too much cholesterol, it can build up and eventually starts to clog or block your arteries. Here are two pictures showing this:

In the first picture, there is more blood and also less cholesterol. In the second picture, there is less blood in the arteries and more cholesterol. This is because the cholesterol clogs the arteries and reduces the amount of blood which flows in them. Because the arteries carry blood from the heart all over the body, this reduces the amount of blood supplied to your body cells.

This can have dangerous and life-threatening effects. Eventually, it may even cause a heart attack. Reducing the amount of fatty food you eat can reduce cholesterol though. It is especially important to avoid trans-fats, a very unhealthy kind of fat. Eating fruits and vegetables can also help reduce cholesterol. It is also helpful to get exercise. Playing outside, riding a bicycle, or playing your favourite sport are all good activities.

title: Wikijunior:Human Body/Blood Vessels


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User talk:83.131.146.206

Thanks for experimenting with Wikibooks. Your test worked, and has now been removed. Please use Sandbox for any other tests you want to do, since testing material in modules will normally be removed quickly. Please see the welcome page if you would like to learn more about contributing to our project. Thanks. -- Herby talk thyme 11:42, 30 May 2007 (UTC)

title: User talk:83.131.146.206


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User talk:4.20.75.148

Thanks for experimenting with Wikibooks. Your test worked, and has now been removed. Please use Sandbox for any other tests you want to do, since testing material in modules will normally be removed quickly. Please see the welcome page if you would like to learn more about contributing to our project. Thanks. -- Herby talk thyme 12:06, 30 May 2007 (UTC)

title: User talk:4.20.75.148


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Belarusian/Lesson 8

Д/ДЗ and Т/Ц Transformations (Diekannie and Tiekannie)
With most consonants, their hard and soft modifications are denoted by a single letter. The exceptions are д and т. When they get to a soft position, they transform to дз and ц respectively. Soft дз and ц do not stand for hard дз and ц.

кот "kot" a cat - ко́цік "kotik" a cat (diminutive)

вада́ "vada" water - вадзіца "vaditsa" water (diminutive)

This has some phonetical background, however. The soft д and ц sounds have light shades of дз and ц sounds (not so in Russian or Ukrainian). Similarly, the soft з and с sounds are pronounced with shades of ж and ш respectively.

Possessives
Here is a chart of all Belarusian possessives, with their gender and number modifications.

The forms in parentheses are more common in colloquial speech, while the other are slightly more formal.

Мой саба́ка стары́. My dog is old.

Твае́ кнігі ціка́выя. Your books are interesting.

Яе́ го́лас прыго́жы. Her voice is beautiful.

На́ша ха́та но́вая. Our house is new.

Ва́шае акно́ шыро́кае. Your window is broad.

The possessives can be used not only as noun attributes, but as pronouns as well. Consider the examples below.

Гэ́та мая́ пра́ца. This is my work.

Гэ́тая пра́ца мая́. This work is mine.

Asking about Possession and Properties
To ask about possession, a question word чый can be used. It is deflected by gender and number.

'''Чый гэ́та ало́вак? - Гэ́та мой ало́вак. Ён мой.''' Whose pencil is this? It is my pencil. It is mine.

'''Чыё гэ́та дрэ́ва? - Гэ́та на́шае дрэ́ва. Яно́ на́ша.''' Whose tree is that? It is our tree. It is ours.

'''Чыя́ гэ́та кніга? - Гэ́та ва́шая кніга. Яна́ ва́ша.''' Whose book is this? It is your book. It is yours.

'''Чые гэ́та каты́? - Гэ́та іх каты́. Яны́ іхныя.''' Whose cats are those? Those are their cats. They are theirs.

With чый both гэта and гэты (in an appropriate flexion) can be used. Note a light difference between them.

'''Чыя́ гэ́та зямля́? - Гэ́та на́шая зямля́.''' Whose land is this? This is our land.

'''Чыя́ гэ́тая зямля́? - Яна́ на́ша.''' Whose is this land? It is ours.

Thus, the first variant is more suitable for the first mentioning of the object, while the second more likely corresponds to the situation when the object has already been mentioned before. However, these variants are interchangeable.

The word чый (in neuter form) can be used alone, when you don't want to name the thing you are asking about (or do not know its name):

'''Чыё гэ́та? - Гэ́та маё.''' Whose is this (i.e. what I am pointing at)? Its mine.

Another question word, які, is used to ask about properties.

'''Які гэ́та го́рад? - Гэ́та вялікі го́рад.''' What kind of town is that? It is a big town.

'''Яко́е гэ́та по́ле? - Гэ́та шыро́кае по́ле.''' What kind of field is that? It is a broad field.

'''Якая гэ́та ка́зка? - Гэ́та ціка́вая ка́зка.''' What kind of tale is this? This is an interesting tale.

'''Які́я гэ́та пту́шкі? - Гэ́та прыго́жыя пту́шкі.''' What kind of birds are those? Those are beautiful birds.

The word які may imply an answer containing a description, or an answer containing a definition. E.g. with the question

Яка́я гэ́та краіна? What (what kind of) country is this?

the following answers are equally correct.

Гэ́та вялікая краіна. This is a big country.

Гэ́та Фра́нцыя. This is France.

To emphasise that you want to hear a definition, not a description, you may use a што ... за construction (note, however, that it is a colloquialism).

'''Што гэ́та за го́рад? - Гэ́та Мінск.''' What city is this? This is Minsk.

'''Што гэ́та за мо́ра? - Гэ́та Балты́йскае мо́ра.''' What sea is this? This is the Baltic sea.

'''Што гэ́та за пту́шкі? - Гэ́та саро́кі.''' What birds are those? Those are magpies.

With people, it is not polite to use што ... за. You should use хто instead.

'''Хто гэ́ты чалаве́к? - Гэ́та дырэ́ктар.''' Who is this person? This is the manager.

'''Хто гэ́тыя лю́дзі? - Гэ́та мае́ выкла́дчыкі.''' Who are these people? These are my lecturers.

Notice that людзі is the plural for чалавек.

Possessives
With the given words, ask questions about possession, and give seven different answers to them (using different possessives).

Sample: a cow - Чыя гэта карова? Гэта мая карова. Гэта твая карова. Гэта яго карова. Гэта яе карова. Гэта наша карова. Гэта ваша карова. Гэта іхная карова.

(1) a passport

(2) a mirror

(3) a hut

(4) books

Clue: (1) Чый гэта пашпарт? Гэта мой пашпарт. Гэта твой пашпарт. Гэта ягоны пашпарт. Гэта яе пашпарт. Гэта наш пашпарт. Гэта ваш пашпарт. Гэта іх пашпарт. (2) Чыё гэта люстра? Гэта маё люстра. Гэта тваё люстра. Гэта ягонае люстра. Гэта яе люстра. Гэта нашае люстра. Гэта вашае люстра. Гэта іх люстра. (3) Чыя гэта хата? Гэта мая хата. Гэта твая хата. Гэта яго хата. Гэта яе хата. Гэта нашая хата. Гэта вашая хата. Гэта іхная хата. (4) Чые гэта кнігі? Гэта мае кнігі. Гэта твае кнігі. Гэта ягоныя кнігі. Гэта яе кнігі. Гэта нашыя кнігі. Гэта вашыя кнігі. Гэта іхныя кнігі.

Asking and Answering
Build questions and answers with the following word and phrase pairs. Be sure to use the appropriate question words and correct gender and number flexions with adjectives and question words.

Sample: city, Paris - Што гэта за горад? Гэта Парыж.

(1) voice, her

(2) river, narrow

(3) river, the Danube

(4) young woman, his secretary

(5) old dog, my

(6) dog, old

(7) book, interesting

Clue: (1) Чый гэта голас? Гэта яе голас. (2) Якая гэта рака? Гэта вузкая рака. (3) Што гэта за рака? Гэта Дунай. (4) Хто гэтая маладая жанчына? Гэта ягоная сакратарка. (5) Чый гэты стары сабака? Гэта мой сабака (or Ён мой). (6) Які гэта сабака? Гэта стары сабака. (7) Якая гэта кніга? Гэта цікавая кніга.

Translation
Translate into Belarusian.

(1) "What is this?" "This is a river". "What river is this?" "This is the Volga."

(2) "Who is this?" "This is a cat." "Whose cat is this?" "This is her cat."

(3) "Who is this tall man?" "This is our manager."

(4) "Whose is this book?" "It is mine." "Is your book interesting?" "No, it is not."

(5) "Is that house yours?" "No, it is not my house." "It is his house."

(6) "What bird is this?" "This is a crow." "Is this crow old?" "No, it is not old. It is young."

Clue: (1) Што гэта? - Гэта рака. - Што гэта за рака? - Гэта Волга. (2) Хто гэта? - Гэта кот. - Чый гэта кот? - Гэта яе кот. (3) Хто гэты высокі чалавек? - Гэта наш дырэктар. (4) Чыя гэта кніга? - Гэта мая кніга. - Твая кніга цікавая? - Не, яна не цікавая. (5) Тая хата твая? - Не, гэта не мая хата. - Гэта ягоная хата. (6) Што гэта за птушка? - Гэта варона. - Гэтая варона старая? - Не, яна не старая. Яна маладая.

title: Belarusian/Lesson 8


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Cookbook:Green Mango and Cumin Drink (Aam Panna)

| Cuisine of India

Aam panna or aam jhora is a green mango drink widely consumed in northern India during summer months. Apart from being delicious and refreshing, aam panna is believed to have several health benefits.

The recipe calls for green (unripe) mangoes, sugar, rock salt, roasted cumin seeds and mint leaves. The quantities can (and should) be varied to suit individual taste preferences. This recipe yields a concentrate which can be stored for around 2 weeks in the refrigerator.

Ingredients

 * 4 medium-sized green mangoes
 * ½ cup (120 ml) sugar
 * 2 level tablespoons (30 ml) rock salt
 * 1 level teaspoon (5 ml) roasted cumin seeds
 * 1 roasted chile (optional)
 * 1 handful of fresh mint leaves

Procedure

 * 1) Cut mangoes into 3 slices each—2 from either side of the seed and 1 with the seed in it.
 * 2) Pressure cook mangoes with one small cup of water. Turn off heat as soon as the pressure cooker whistles once.
 * 3) Open cooker after 5–7 minutes and leave to cool.
 * 4) Grind sugar and roasted cumin seeds using a food processor. If using chilli, grind that too.
 * 5) Mince mint leaves in a food processor.
 * 6) When cool, squeeze pulp of mangoes into a blender using hands. Discard skin and seeds.
 * 7) Purée mango pulp until smooth.
 * 8) Add ground sugar, rock salt, roasted cumin seeds, chilli powder, and minced mint leaves. Blend well.
 * 9) Store in clean plastic or glass bottle. Refrigerate.
 * 10) To serve, add 4–5 teaspoons of the mango mixture to a glass of water. Enjoy!

Notes, tips, and variations

 * Instead of pressure cooking the mangoes you can roast the whole mangoes over an open flame, until the skin is charred and the flesh is soft. The charred skin will peel off easily and you can squeeze out the pulp with your hands. This gives a nice smoky flavour to the dish.

Recipe Video
Aam Panna/Jhora


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Talk:Abstract Algebra/Integral domains

"Theorem: Let R be an integral domain and let R[x] be the ring of polynomials in powers of x whose coefficients are elements of R. Then R[x] is an integral domain if and only if R is." First you say R is an integral domain, then you say .. is an integral domain if"f R is. 85.250.34.21

title: Talk:Abstract Algebra/Integral domains


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Cookbook:Easy Pasta Sauce

This a very easy and tasty pasta sauce. It's good with just pasta, and goes well with a lot of vegetables as well. The quantities of ingredients vary with the amount of pasta, and with your taste preferences.

Ingredients

 * Olive oil
 * Garlic cloves
 * Ripe tomatoes
 * Salt
 * Ground black pepper
 * Fresh cream
 * Oregano
 * Additional ingredients, as desired

Procedure

 * 1) Finely chop tomatoes or purée them in a food processor—this depends on what consistency you want. Chopping gives a chunkier sauce while using puréed tomatoes yields a smoother sauce.
 * 2) Grind garlic to paste.
 * 3) Heat oil in a frying pan. Using a pan with non-stick coating necessitates less oil.
 * 4) When oil is hot (but not too hot), turn down heat and add garlic paste.
 * 5) When garlic is golden-brown, add tomatoes.
 * 6) Tomatoes have to be cooked until done—they'll look and smell cooked instead of raw, and will be a deeper, redder colour.
 * 7) Add salt and pepper to taste.
 * 8) When tomatoes are almost done, add fresh cream to taste. Cook for about 30 seconds.
 * 9) Add oregano, then cook for another minute.
 * 10) Add cooked pasta and vegetables.
 * 11) Serve hot, garnished with herbs (e.g. basil, rosemary).

title: Cookbook:Easy Pasta Sauce


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Template:The Seven Wonders of the World

The Seven Wonders of the World The Seven Wonders — The Great Pyramid — The Hanging Gardens — The Statue of Zeus — The Temple of Artemis — The Mausoleum — The Colossus — The Pharos

title: Template:The Seven Wonders of the World


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Principles of Finance/Section 1/Chapter 2/Time Value of Money/Opportunity Cost

The opportunity cost of capital is the amount of money you forego by investing money in one asset compared to another. For eg. If you have only two alternatives a) Invest in an asset which gives 5% return        b) Invest in another asset which gives 6% return If you choose the first option, you wont be able to take advantage of the second option. The difference between what you are earning and what you could be earning is the opportunity cost of capital. In this scenario it is 1% (6%-1%). Take another example: say you have a piece of land kept idle. If you make a warehouse over it ,then you cannot use it for any other purpose. So, you miss the earning possibility from any alternative use. That is your opportunity cost.


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The Seven Wonders of the World/The Seven Wonders

The "seven wonders of the world" was a list of spectacular buildings and structures, compiled by Greek authors. The list that we currently use today was compiled by historians in the 6th century AD from the original Greek writings. Because all the original sources were Greek, all of the wonders in the list are located in Greece and surrounding areas by the eastern end of the Mediterranean Sea.

With the exception of the great pyramid all the seven wonders have been destroyed by natural disaster, predominantly fires and earthquakes.

The first surviving Greek record of the seven wonders was given by Antipater of Sidon, who wrote about them in a poem:

This original list includes Babylon's Ishtar Gate instead of the lighthouse at Alexandria, although later lists exclude the gate in favor of the lighthouse.

Biography: Antipater of Sidon
Every page is going to include at least historical vignette about one of the people (or a group of people) who are associated with that wonder. Because Antipater of Sidon is the earliest surviving record of the seven wonders being listed, we will discuss him here.

Antipater of Sidon (2nd century BCE) is an ancient Greek writer and poet best known for his list of Seven Wonders of the World. He and the mathematician and engineer Philo of Byzantium (born about 280 BCE) are known as the most famous observers of the Seven Wonders. Antipater's poem describes the 7 Magnificent Wonders he had seen, the ones we call the 7 wonders even today. For the idea of 7 monuments that show the significance of mankind was so greatly treasured it was kept alive...family to family...generation to generation. Then in around AD 1500 the Renaissance in Europe became interested in ancient times, and miraculously Antipater’s poem and many other short poems or stories of Greek marvels were rediscovered. It is from these rediscovered poems and descriptions that much of our current knowledge of the seven wonders exists today.


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The Seven Wonders of the World/The Great Pyramid

The Great Pyramid at Giza is the only one of the seven wonders that is still standing today. Built by the Egyptians between 2575-c. 2465 BCE, the Great Pyramid is one of many large pyramid structures built to honor dead Pharaoh. The Giza Plateau, or "Giza Necropolis" in the Egyptian Valley of the Dead contains several pyramids (of which the great pyramid is the largest), several small tombs, several temples, and the great Sphinx. The great pyramid was created to honor the Pharaoh Khufu, and many of the smaller pyramids, tombs, and temples were built to honor Khufu's wives and family members.

Biography: Khufu

Khufu was the son of King Sneferu, and Queen Hetepheres. Khufu is remembered as a cruel and ruthless Pharaoh in later folklore. Khufu had nine sons, one of whom, Djedefra, was his immediate successor.

It is generally thought that Khufu came to the throne in his twenties. Accounts differ on how long he was Pharaoh, with accounts claiming he ruled for anywhere between about 23 years to 65 years. He started building his pyramid at Giza, the first to be built in that place. Based on inscriptional evidence, it is also likely that he led military expeditions into the Sinai, Nubia and Libya.

The Westcar Papyrus, which was written well after his reign during the Middle Kingdom or later, depicts the Pharaoh being told magical tales by his sons Khafra and Djedefra. This story cycle depicts Khufu as mean and cruel, and is ultimately frustrated in his attempts to ensure that his dynasty survives past his two sons. Whether or not this story cycle is true is unknown, But Khufu's negative reputation lasted at least until the time of Herodotus, who was told further stories of that king's cruelty to his people and to his own family in order to ensure the construction of his pyramid. What is known for certain is that his funerary cult lasted until the 26th Dynasty, which was one of the last native-Egyptian royal dynasties, almost 2,000 years after his death.

Most likenesses of Khufu are lost to history. Only one miniature statuette (right) has been fully attributed to this Pharaoh. Since he is credited with building the single largest building of ancient times, it is ironic that the only positively identified royal sculpture of his is also the smallest that has ever been found: a 7.6cm (3 inch) ivory statue that bears his name. It was discovered not at Giza, but in a temple in Abydos during an excavation by William Matthew Flinders Petrie in 1903. Originally this piece was found without the head, but bearing the Pharaoh's name. Realizing the importance of this discovery, Petrie halted all further excavation on the site until the head was found three weeks later. This statue is now on display in the Egyptian Museum, Cairo.

Location: Giza
The Giza plateau is an area outside of modern day Cairo. Because of the several pyramids, tombs, and graveyards on the plateau, the area is commonly known as the "Giza Necroplex". The plateau itself is part of the town of Giza.

Giza is 20 miles away from the Nile river, and has become part of the Cairo metropolis. Many images of the Giza plateau show a vast desert, but modern day Giza is a thriving town with a substantial population. During British colonization in the 19th and early 20th centuries, many roads and buildings were constructed in the area to help support the local commerce.


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A-level Chemistry/OCR (Salters)/IR

Infrared spectroscopy is a spectroscopic technique used for structure determination. You can use the infrared spectrum of an unknown compound to help identify it.

Animations
animation of C=O stretching in propanone (5.4 MB)

title: A-level Chemistry/OCR (Salters)/IR


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The Seven Wonders of the World/The Hanging Gardens

Of all the seven wonders, the hanging gardens of Babylon are perhaps the most elusive. In fact, besides writings from Greek historians, there are no records and no evidence to prove that the hanging gardens of Babylon ever existed. There are not even any Babylonian records or accounts of any hanging gardens.

Tradition says that the hanging gardens were constructed by king Nebuchadnezzar II as a gift for his wife Amyitis of Media.

Large gardens did exist at Nineveh, and it is believed by some historians that accounts of the hanging gardens of Babylon actually referred to the gardens at Nineveh. Tablets recovered from archeological digs at Ninevah show large above-ground gardens, and writings from tablets at Nineveh describe devices similar to Archimedies' Screws that could be used to bring water to the gardens above.

Biography: Nebuchadnezzar II

Nebuchadnezzar II (sometimes also written as Nebuchadrezzar II) was a king of ancient babylon who reigned c. 605 BC-562 BCE. He is famous for his conquests of Judah and Jerusalem, his monumental building within his capital of Babylon, his role in the Book of Daniel, and his construction of the Hanging Gardens of Babylon, which as legend has it, he made for his wife Amytis of Media because she was homesick for the mountain springs where she grew up.

He is traditionally called "Nebuchadnezzar the Great", but his destruction of temples in Jerusalem and the conquest of Judah caused his vilification in Judaic tradition and in the Bible, (Daniel 1:1; Prophesied Jeremiah 25:11) causing him to be interpreted very differently by western Christians and Jews than in contemporary Iraq, where he is glorified as an historic leader.

Location: Babylon
Babylon was an ancient city in Mesopotamia (modern Al Hillah, Iraq), the ruins of which can be found in present-day Babil Province, about 80 km south of Baghdad. The city itself was built upon the Euphrates, and divided in equal parts along its left and right banks, with steep embankments to contain the river's seasonal floods. Babylon grew in extent and grandeur over time, but gradually became subject to the rule of Assyria.

During the reign of Sennacherib of Assyria, Babylonia was in a constant state of revolt, led by Mushezib-Marduk, and suppressed only by the complete destruction of the city of Babylon. With the recovery of Babylonian independence, a new era of architectural activity ensued, and Nebuchadnezzar II made Babylon into one of the wonders of the ancient world. Nebuchadnezzar ordered the complete reconstruction of the imperial grounds, including rebuilding the Etemenanki ziggurat and the construction of the Ishtar Gate — the most spectacular of eight gates that ringed the perimeter of Babylon. The Ishtar Gate survives today in the Pergamon Museum in Berlin.

In 539 BC the Neo-Babylonian Empire fell to Cyrus the Great, king of Persia. It is said that Cyrus walked through the gates of Babylon without encountering any resistance.

In 331 BC, Darius III was defeated by the forces of the Macedonian ruler Alexander the Great at the Battle of Gaugamela, and in October, Babylon fell to the young conqueror. A native account of this invasion notes a ruling by Alexander not to enter the homes of its inhabitants.

Under Alexander, Babylon again flourished as a centre of learning and commerce. But following Alexander's death in 323 BC in the palace of Nebuchadnezzar, his empire was divided amongst his generals, and decades of fighting soon began, with Babylon once again caught in the middle.


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The Seven Wonders of the World/The Statue of Zeus

The statue of Zeus from the temple at Olympia was a gigantic statue constructed by Phidias in the fifth century BCE. It was constructed of a wooden frame covered in carved ivory with gold accents. In the sculpture, he was seated on a magnificent throne of cedarwood, inlaid with ivory, gold, ebony, and precious stones. In Zeus' right hand there was a small statue of Nike, the goddess of victory, and in his left hand, a shining sceptre on which an eagle perched. Plutarch, in his Life of the Roman general Aemilius Paulus, records that the victor over Macedon "was moved to his soul, as if he had beheld the god in person," while the Greek orator Dio Chrysostom wrote that a single glimpse of the statue would make a man forget his earthly troubles. The temple of Zeus, where the statue stood, was destroyed by fire in the fourth century BCE, although some scholars believe that the statue had been moved to Constantinople before the fire, and was later destroyed there.


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The Seven Wonders of the World/The Temple of Artemis

The temple of Artemis at Ephesus was a large stone temple constructed around 550 BCE.

The temple of Artemis at Ephesus was destroyed on July 21, 356 BCE in an act of arson committed by Herostratus. According to the story, his motivation was fame at any cost. The Ephesians, outraged, announced that Herostratus' name never be recorded. The Greek historian Strabo later noted the name, which is how we know today. The temple was destroyed on the same night that Alexander the Great was born. Alexander, as king, offered to pay to rebuild the temple, but his offer was denied. Later, after Alexander died, the temple was rebuilt in 323 BCE.

The new temple was destroyed by the Goths in 262 BCE. The temple was rebuilt again, only to collapse. During a dispute between followers of Artemis and the Apostle John (see Acts of John) This event causes the eventual disbanding of the cult of Artemis, and the mass conversion of the Ephesians to christianity.


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The Seven Wonders of the World/The Mausoleum

The Mausoleum of Halicarnassus, also known as the Mausoleum of Maussollos was a tomb built in the fourth century BCE in honor of Mausolus and his wife Artemisia. The Mausoleum stood approximately 135 feet (41 meters) tall, and each wall was adorned with carvings by one of four great Greek sculptors.

Etymology: "Mausoleum"
The word "Mausoleum" is actually a combination of the original Greek words "Mausol" and "eion", or "dedicated to Mausol". Because this tomb was so grand, all other large tombs have been known as mausoleums.

Biography: Mausolus
The Mausoleum is dedicated to a man named Mausolus, who was a Persian Governor of Anatolia. In addition to creating many new cities, buildings and other large construction projects, Mausolus founded the city of Halicarnassus to be the capital of Anatolia. Mausolus, as was custom among Persian officials at the time, married his sister Artemisia. After Mausolus' death, Artemisia finished constructing the large mausoleum in his honor.


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User talk:Smkolins

Hello, welcome to Wikibooks!

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Good luck! Mattb112885 (talk) 14:44, 30 May 2007 (UTC)

title: User talk:Smkolins


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User:Smkolins

Hi!

title: User:Smkolins


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The Seven Wonders of the World/The Colossus

The Colossus at Rhodes, a gigantic statue of the Greek god Helios, was constructed in the third century BCE. The statue stood over 30 meters tall at the mouth of the harbor at Rhodes. After Alexander the Great died, his empire was broken into several pieces by his generals. Ptolemy, who was in control of Rhodes and Egypt, controlled much of the commerce on the Mediterranean. Fighting broke out between Ptolemy at Rhodes and another of Alexander's generals. After the fighting was over, the vicorious Rhodians used war plunder to construct the Colossus.

The statue was constructed by Chares of Lindos out of a combination of stone, iron, and bronze. Large stone support pillars were erected at the mouth of the harbour, and embedded with iron cross-bars. The iron bars then were covered with sculpted bronze plates to form the finished colossus.

An earthquake in 226 BCE destroyed the statue, which cracked at the knees and fell onto the land. The Rhodians choose not to rebuild it because the Oracle at Delphi warned that it would anger the god Helios. The statue lay on the ground untouched for over 800 years, and was a popular tourist attraction. In 654 an Arab force under Muawiyah I captured Rhodes and the remains were sold to a traveling salesman from Edessa. The buyer had the statue broken down, and transported the bronze scrap on the backs of 900 camels to his home. Pieces continued to turn up for sale for years, after being found along the caravan route.


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The Seven Wonders of the World/The Pharos

The Pharos, also known as the lighthouse of Alexandria was a large lighthouse that served as a navigational aide for ships entering the city. The precise height of the lighthouse is not known, but it is estimated by scientists and archeologists to have been between 115 meters and 180 meters tall. The top end of that estimate would have the lighthouse being taller then the great pyramid and therefore the tallest building in the ancient world. The lower end of the estimation, 115 meters, would have been the third largest building in the world, after the great pyramid and the pyramid of Khafra.

The Lighthouse was built on a small island known as Pharos off the coast of Alexandria. The island was connected to the mainland by a man-made connector that formed one side of the Alexandrian harbor. Because the egyptian coast line was so flat and featureless, the lighthouse was an important navigational aide for sailors.

The structure was originally designed as being simply a tall tower to serve as a marker, but fire and mirrors were added to make it a true lighthouse in the first century BCE.

Earthquakes in 1303 and 1323 CE turned the lighthouse into a ruin. In 1480 Qaitbay the sultan of Egypt built a medieval fort on the former location of the building, using some of the fallen stone. The remnants of the Pharos that were incorporated into the walls of Fort Qaitbey are clearly visible due to their excessive size in comparison to surrounding masonry.


text: Category:Book:The Seven Wonders of the World


text: User:Stephanvaningen

title: User:Stephanvaningen


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Music Theory/Counterpoint/Species Counterpoint

Species Counterpoint is that method of teaching laid out most famously by Johann Joseph Fux in his treatise Gradus ad Parnassum. Its method relies upon breaking contrapuntal study into five parts for each combination of two, three and four voices. The five parts (or "species") are as follows:

The first species is note-against-note counterpoint.

The second species is two notes against one in the cantus firmus.

The third species is four notes against one in the cantus firmus.

The fourth species is the study of suspensions against a cantus firmus.

The fifth species describes the combination of the four previous species together against a cantus firmus.

/In Two Voices/
This is the simplest of possible contrapuntal compositions. It consists of one cantus firmus and one composed "counterpoint" to it.

/In Three Voices/
Fux describes three-voice counterpoint as the most perfect because it is the only type in which it is possible to create complete harmonic triads without having to use an extra voice. That is, compositions which use more than three voices end up doubling triadic pitches, like the octave and the third. Put another way, three voice composition is the most perfect because it is the only way to express complete harmonic triads using a minimum of voices.

/In Four Voices/
Four voice contrapuntal composition necessarily requires that, at least in harmonic triads, one of the voices be doubled. An exception arises in the creation of dissonant chords, like the dominant seventh chord.

/More Than Four Voices/
Fux ends his book with the treatment of florid counterpoint (5th species) in four voices. Compositions which treat five or more voices are not much different than those treating four voices (and we know that treating four voices is not much different than treating three). Greater care must be taken in composing in more than four voices because as the texture becomes thicker, so it becomes more prone to error. All rules which apply to four voice writing also apply to all writing beyond four voices. If you write with more than four voices it might turn out strangely because you will have to double up a lot.