.Dd $Mdocdate: March 05 2012$
.Dt GNS3 1
.Os
.Sh "NAME"
.Nm gns3
.Nd a graphical network simulator
.Sh "SYNOPSIS"
.Nm gns3
.Op -cdh
.Op file
.Sh DESCRIPTION
GNS3 is a graphical network simulator that allows simulation of
complex networks and to launch simulations on them. It is an excellent
complementary tool to real labs for administrators of Cisco networks
or people wanting to pass their CCNA, CCNP, CCIP or CCIE certifications.
It can also be used to experiment features of Cisco IOS or to check
configurations that need to be deployed later on real routers.
.Pp
To allow complete simulations, GNS3 is strongly linked with :
.Bl -bullet -offset 1c
.It
Dynamips, the core program that allows Cisco IOS emulation
.It
Dynagen, a text-based front-end for Dynamips
.It
Qemu, a generic and open source machine emulator and virtualizer
.It
VirtualBox, a free and powerful virtualization software.
.El
.Pp
\fIImportant notice:\fP users have to provide their own images.
.Pp
You may have to install a patched version of some emulators, please read
the online documentation.
The options are as follows:
.Bl -tag -width 3c
.It Fl h
Displays a help message
.It Fl c
Directory where gns3.ini is located (default: ~/gns3/)
.It Fl d
Display debug messages
.It Fl -version
Prints out the version and exits
.El
.Sh ONLINE DOCUMENTATION
Check out the online documentation at http://www.gns3.net
.Sh REPORTING BUGS
Please send bug reports at http://redmine.gns3.net
.Sh SEE ALSO
.Xr qemu 1 ,
.Xr dynamips 1
.Sh "AUTHOR"
GNS3 has been written by Jeremy Grossmann, David Ruiz, Romain
Lamaison, Aurelien Levesque, Xavier Alt, Benjamin Marsili,
Claire Goudjil and Alexey Eromenko "Technologov". 
The developers can be contacted using this form:
http://www.gns3.net/contact