"Secure your Network with Open Source Applications and Tools "

Wikipedia - “Network security consists of the provisions and policies adopted by a network administrator to prevent and monitor unauthorized access, misuse, modification, or denial of a computer network and network-accessible resources.”

In today’s world securing information is most critical and difficult part in any organization. Your development and research team will come up with some of the best ideas and products, but in the end somebody else may end up enjoying benefits out of it. You will never know while you are sleeping, your employee may steal data from your premise or your corporate enemies may launch a cyber attack on your network.

In order to secure your network you will find lot of applications, hardware and tools which are available in market. However I will try to explain very few of open source tools from load of tools which are freely available. The reason for going with open source is simple, it’s open. You know what is application/tool is doing and you have full control on it. Should your company follow the crowd moving towards open source network security? That depends on which is more important to you: an agile solution that doesnt cost much or a comprehensive solution that comes with plenty of support. If you are looking for the agile solution read on…

IP COP – IPCOP comes with bundle of tools and applications built in. It has transparent proxy server, web caching tools, advanced proxy for controlling your traffic, DHCP server, firewall, IP tables for those fine tuning, URL filtering for blocking chat etc, port forwarding for getting specific traffic into your network. Just put in on your internet pipe and you are up and running. It will secure network and keep inform you once something goes wrong. It can run on old PII or PIII machine with 512 MB RAM and is not resource intensive. You can access the website at http://www.ipcop.org/

OpenVPN – You must be using paid VPN software or hardware to connect to your office network. Try Open VPN, It’s an excellent tool which can be run on Linux box or can be run directly from IPCOP. With OpenVPN you can
•    tunnel any IP subnetwork or virtual Ethernet adapter over a single UDP or TCP port,
•    configure a scalable, load-balanced VPN server farm using one or more machines which can handle thousands of dynamic connections from incoming VPN clients,
•    use all of the encryption, authentication, and certification features of the OpenSSL library to protect your private network traffic as it transits the internet,
You can access further details on http://openvpn.net/

WireShark - Formerly known as "Ethereal," Wireshark is the worlds foremost network protocol analyzer. It allows the user to see all traffic being passed over an Ethernet network. It runs on Windows, Linux, OS X, Solaris, FreeBSD, NetBSD, and others. It shows you any packet travelling on network and can also show you any non encrypted password . Use it for good  http://www.wireshark.org/

NMAP - Nmap ("Network Mapper") is a free and open source utility for network discovery and security auditing. Many systems and network administrators also find it useful for tasks such as network inventory, managing service upgrade schedules, and monitoring host or service uptime. Output of nmap can tell you open ports, running services etc on a network in a minute. NMAP is fastest and most comprehensive way to discover network, running services and holes in security.

Open SSL - The OpenSSL Project is a collaborative effort to develop a robust, commercial-grade, full-featured, and Open Source toolkit implementing the Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS v1) protocols as well as a full-strength general purpose cryptography library. You can compile apache, postfix with SSL support and start your own secure mail delivery on TLS or run https services. SSL will provide secure connectivity between your server and client to exchange data. http://www.openssl.org/

Clam Antivirus – Ever heard of free antivirus which can secure your email gateway for free. Clam is just the right choice if you are looking to implement a low cost email server with full featured antivirus support. ClamAV is an open source (GPL) antivirus engine designed for detecting Trojans, viruses, malware and other malicious threats. It provides a high performance mutli-threaded scanning daemon, command line utilities for on demand file scanning, and an intelligent tool for automatic signature updates. I have personally used it along with postfix and found it as reliable as any commercial grade application. http://www.clamav.net/lang/en/

There are more open source applications and tools which you can utilize in your network and make it more secure and efficient.