GNS3 is a graphical network simulator that allows simulation of complex networks.

To allow complete simulations, GNS3 is strongly linked with :

* Dynamips, the core program that allows Cisco IOS emulation.
* Dynagen, a text-based front-end for Dynamips.
* Pemu, a Cisco PIX firewall emulator based on Qemu.

GNS3 is an excellent complementary tool to real labs for Cisco network engineers, administrators and people wanting to pass certifications such as CCNA, CCNP, CCIP or CCIE.

It can also be used to experiment features of Cisco IOS or to check configurations that need to be deployed later on real routers.

This project is an open source, free program that may be used on multiple operating systems, including Windows, Linux, and MacOS X.
Features overview

* Design of high quality and complex network topologies.
* Emulation of many Cisco router platforms and PIX firewalls.
* Simulation of simple Ethernet, ATM and Frame Relay switches.
* Connection of the simulated network to the real world!
* Packet capture using Wireshark. [via Layertwo]

Visit the Site>> GNS3 Site HERE

Attack code that exploits flaws in the net’s addressing system are starting to circulate online, say security experts.

The code could be a boon to phishing gangs who redirect web users to fake bank sites and steal login details.

In light of the news net firms are being urged to apply a fix for the loop-hole before attacks by hi-tech criminals become widespread. Net security groups say there is anecdotal evidence that small scale attacks are already happening.

Address list
“We are in a lot of trouble,” said security guru Dan Kaminsky who found the flaw in the net’s Domain Name System (DNS) in March 2008. “This attack is very good,” he said. “This attack is being weaponised out in the field. Everyone needs to patch, please.” The DNS acts as the net’s address system and helps computers translate the website names people use, such as bbc.co.uk, into the numerical equivalents preferred by machines.

If exploited the flaw would allow malicious hackers to direct people to fake sites even if that user typed in the correct address for the place they wanted to visit. Now security researchers have come up with two separate methods for attacking the flaw. The code used in the attacks has been added to a popular testing tool called Metasploit used by both good and bad hackers alike to find weaknesses in computer systems. [BBC NEWS]