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.

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.

Important notice: users have to provide their own Cisco IOS to use with GNS3. 
It is also recommended to read the documentation _before_ starting the program.
As of version 0.8.7 the package for dynamips has to be installed separately.
Port 127.0.0.1:7200 has to be open on your firewall.