How to make GNS3/Dynamips communicate with your local network

Posted: November 7, 2010 in Infrastructure Management and Disaster Recovery
1) Install the Microsoft Loopback Adapter as per this guide (Windows 7. Similar process for other Windows versions):
2) Configure the Loopback Adapter with whatever network settings you like
3) Restart the PC. You cannot continue until you restart the PC.
4) Open up a cmd prompt as administrator and navigate to your GNS3 installation directory, something like this:
D:\Program Files\GNS3\
Run this batch file:
Network device list.cmd
It will come up with something like this:
d:\Program Files\GNS3>”Network device list.cmd” 

Network adapters on this machine:

Name      : Local Area Connection* 13
Desciption: Anchorfree HSS Adapter

Name      : VMware Network Adapter VMnet1
Desciption: VMware Virtual Ethernet Adapter

Name      : VirtualBox Host-Only Network
Desciption: Sun

Name      : VMware Network Adapter VMnet8
Desciption: VMware Virtual Ethernet Adapter

Name      : Local Area Connection
Desciption: VIA Rhine II Fast Ethernet Adapter

Name      : Loopback
Desciption: MS LoopBack Driver

Find your loopback adapter and take note of the last few characters of the long code (i.e. 6861 in this example).

5) Run GNS3 as Administrator.
6) Add a Router and a Could.
7) Configure the Cloud. On the NIO Ethernet tab find your loopback device on the dropdown
Add this and return to your project.
8) Start the router and configure it with an IP address which could talk to the one you set on your loopback device.
interface FastEthernet0/0
ip address
duplex auto
speed auto
That’s it! Ping from the router to your desktop and vice versa to prove connectivity. You can now use GNS3 and Dynamips as real routers on your home network, and can make VMs talk to your virtual routers, enabling you to perform network monitoring at home without needing lab access.


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