How to have complete security - (Antivirus, Rootkit, Firewall, Email , Web , Network, IDS, VPN, Encryption)

Antivirus

Perhaps the ultimate definition of computer security is the effectiveness of your antivirus. Antivirus software keeps the most problematic forms of malware from corrupting your computer.
Clam AntiVirus – Extremely popular antivirus solution for UNIX based machines. Includes real time virus scanning and a virus definition database updated multiple times per day.
AVScan – A front-end for Clam AntiVirus.
AVG Anti-Virus – Effective virus scanning suite. Requires regular virus definition updates.
Avast Home Edition – Complete antivirus suite including real time scanning, email protection, internet traffic filtering, a firewall and more.
Housecall – Web based scanner that detects and removes viruses, worms, trojans and spyware. Also points out system vulnerabilities and offers advice on obtaining security patches.
Symantec Security Check – Simple antivirus solution that searches your computer for various forms of malware and deletes them. Offers a secondary scan to measure the vulnerability of your computer.

Rootkit

Rootkits are about the nastiest forms of malware around. To keep your computer (and your privacy) safe, you’ll need an app to scan for rootkits.
chkrootkit – The definitive solution for finding and removing rootkits from Linux machines.

Firewall

A well regarded firewall with a strict rule set is the first line of defense against intruders. Keep hackers from sneaking malware onto your system in the first place with these freebie firewall solutions.
Firestarter – Real time firewall that monitors all of the open ports and active network connections on your computer. Allows you to specify a very strict rule set.
Firewall Builder – Useful tool for assembling a firewall rule set or policy for popular UNIX based firewalls including iptables, ipfilter, etc.
TuxGuardian – Verifies the integrity of applications trying to gain access to the network. Useful for preventing viruses, trojans, spyware, etc. from spreading throughout the network.
HardWall Firewall – Iptables based script that performs detailed packet inspection and filtering to keep your computer free from malicious traffic.
BullDog – Complex firewall for advanced users.
PeerGuardian – Blocks IPs from accessing your network. Especially useful for protecting your privacy when using peer to peer software.

Email Security

Thunderbird – Highly customizable secure email client. Comes equipped with spam email filters, phishing protection and encryption capabilities.
Smart sendmail filters – A collection of tools to block and filter sendmail spam as well as scan attachments for viruses.
Sagator – An interface for the postfix, sendmail and other smtpd gateways that run popular antivirus and antispam solutions.
Tiger Envelopes – Encrypts email messages. Integrates into Outlook, Thunderbird, Mac Mail and KMail.

Web Utility

Malware infestation is probably the most annoying aspect of surfing the internet. It starts by accidentally downloading a toolbar here, failing to read a EULA there, and eventually your whole computer is one big slow piece of junk. To prevent this from happening (again) try using these apps when surfing.
Tor – Uses a network of virtual tunnels to provide anonymity for surfing the internet and transferring files over a network.
Firefox – A fan favorite browser for it’s secure architecture and available add-ons. Uses SSL browsing by default.
WebCleaner – Allows you to control the type of data your proxy parses. Useful for eliminating dangerous malware and removing annoying popup ads.
McAfee Site Advisor – Rates websites by their ability to infect your computer with malware. Advises you if a site is safe or not.

Network

With an insecure network not only will you be vulnerable to the perils of the internet, everyone connected to your network will too. Meaning instead of having one computer down due to a nasty virus, you could have hundreds. These freebie apps will help you manage the challenge of keeping your network safe.
SmoothWall – Firewall, IDS and VPN system for home users and networks.
Nagios – Comprehensive web based tool equipped with virtually every imaginable feature for knowing exactly what’s going on in your network.
Nessus – Industry leading open source network vulnerability scanner. Highly scalable and very thorough.
Wireshark – Powerful tool for capturing network protocol data for analysis. Contains more than 25 methods for reading packets making it useful for a wide array of networks.

Intrusion Detection System

Implementing an effective intrusion detection system is a surefire step to improving the security of your network and personal computer. Here are several popular solutions.
Snort – The premier free IDS solution. Detects a wide variety of attacks including buffer overflows, OS fingerprinting, CGI scans and more. Uses real time traffic analysis and packet logging on IP networks
Open Source Host-based Intrusion Detection System – Personal IDS performing log analysis, registry monitoring, malware detection, time-based alerting and active response.
Prelude – Detects system anomalies and reports findings to the user. Also analyzes logs for anomalies.

Virtual Private Network

VPN usage has exploded the past few years due to its new found ease of use and high level of security.
SSL-Explorer – Highly scalable VPN that integrates directly into your browser. Requires only a single open port to work.
OpenVPN – Popular VPN solution specializing in remote access.
strongSwan – IPsec based VPN using multiple encryption methods.

Encryption

Encryption is a must for the most sensitive types of data. After all, we all know what happens when a password or credit card number winds up in the wrong persons hands. That’s why we recommend you check out a few of the following encryption apps.
GNU Privacy Guard – A command line based encryption tool using multiple encryption algorithms including OpenPGP, AES, SHA-1, and more.
TrueCrypt – Creates virtual encrypted drives.