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firewall is an integrated collection of security measures designed to prevent unauthorized electronic access to a networked computer system. It is also a device or set of devices configured to permit, deny, encrypt, decrypt, or proxy all computer traffic between different security domains based upon a set of rules and other criteria.

IPSec policies can be applied locally or be applied to a member of a domain as part of that domain’s group policies. Local IPSec policies can be static (persistent after restarts) or dynamic (volatile). Static IPSec policies are written to the local registry and persist after the operating system is restarted. Dynamic IPSec policies are not permanently written to the registry and are removed if the operating system or the IPSec Policy Agent service is restarted.

To change the default security level for a zone, customize security options in a zone, or assign a Web site to a specific zone. To do this, follow the steps in one of the following sections.
How to Change the Default Security Level for a Zone
loadTOCNode(3, ‘moreinformation’); For each security zone in [...]

The Custom option gives advanced users and administrators more control over all security options. For example, the Download Unsigned ActiveX Controls option is disabled by default in the Local Intranet zone (Medium security is the default setting for the Local Intranet zone). In this case, Internet Explorer [...]

A VPN is a method of connecting to a private network (for example, your office network) by way of a public network (for example, the Internet).
A VPN gives you the benefit of a dial-up connection to a dial-up server, plus the ease and flexibility of an Internet connection. Using [...]

On a Windows XP-based computer, you can share files among both local and remote users. Local users log on to your computer directly through their own accounts or through a Guest account. Remote users connect to your computer over the network and access the files that are shared on your computer.
You can access the Simple [...]

Webmin is a web-based interface for system administration for Unix. Using any browser that supports tables and forms (and Java for the File Manager module), you can setup user accounts, Apache, DNS, file sharing and so on.
Webmin consists of a simple web server, and a number of CGI programs which directly update system files like [...]

If you want to crack zip file passwords use fcrackzip.fcrackzip is a fast password cracker partly written in assembler. It is able to crack password protected zip files with brute force or dictionary based attacks, optionally testing with unzip its results.
Install fcrackzip in Ubuntu
sudo aptitude install fcrackzip
This will complete the installation.

Fcrack Syntax
fcrackzip [-bDBchVvplum2] [--brute-force] [--dictionary] [...]

This tutorial describes how to install Ubuntu by copying the contents of the installation CD to an USB memory stick (aka flash drive) and making the stick bootable. This is handy for machines like ultra portable notebooks that do not have a CD drive but can boot from USB media.
In short here’s what you do:
Prepare [...]

A mail transport agent (MTA) provides the “plumbing” for your email system by taking mail from a client application such as Evolution or Mozilla Thunderbird and routing it to the correct location on the right machine. There are plenty of good MTAs, such as Postfix, Sendmail, and qmail, but these popular mail servers require a large amount of configuration, and may be overkill for users who merely want to set up an MTA to test a Web development project or need to move mail around locally. Smail is a better alternative for these scenarios because it generally requires no configuration, and its memory footprint is less than the more fully featured MTAs.