When you are working in a Cisco Lab environment you cant keep on changing the console cable from one router to another for configuration for this purpose an access server is used. Access server has several config cables coming out from a single port. These cables can be connected to different routers in the network. Now while only logging into a single router we can configure all the other routers that are connected using the special cable.
Now this is the case with real routers, when you are using GNS3 as simulator then it also becomes a hassle to manage the console of each router. Tools like puttycm and secureCRT can be used but still these have multiple consoles.
There is one cool way to use a router as an ACCESS server in GNS3
Now to configure ACCESS router in GNS3 follow the steps :-
Step1.) This requires the installation of a microsoft loopback adapter. Access server will use this adapter as a mean to connect the other routers.
Step2.) To add a microsoft loopback adapter open device manager. In windows 7 you can right click the my computer icon -> click properties then a window appears now click on device manager.
Step3.) Now in device manager goto ACTION tab and click on add legacy hardware. A screen like this will appear.
Now click on NEXT.
Step4.) Now select . Install the hardware manually from list.
Step5.) Select Network Adapters from the list.
Step6.) Select the Microsoft from the Manufacturer’s list and loopback adapter from the network adapters list.
Step7.) Now after finishing the install Reboot the computer. For loopback adapter to work correctly it is necessary to reboot.
Step1.) Now open GNS 3 and drag a cloud. Right click the cloud and click on NIO ethernet tab.
Step2.) Now select the microsoft loopback adapter from the list of ethernet cards and click on add. Now connect the router to cloud using a fastethernet connection.
Step3.) Now add the routers to the scenario to which you want the access server to connect. I am adding two routers R2 and R3.
Now the scenario should look something like this.
Step4.) Right click the routers R2 and R3 and click on change console port. You will get the screens like this. Note down the port numbers. These port numbers will be used by access server in gns3 to connect to router R2 and R3 using router R1 which is access server.
Step5.) Now start the Router R1 and login to global configuration mode.
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#int fastEthernet 0/0
R1(config-if)#ip address 192.168.1.2 255.255.255.0
Step6.) Now navigate to control panel-> Network and sharing centre-> change adapter setting. Select the microsoft loopback adapter and right click. Click on properties and select the IPv4 again click on properties. Now enter the following ip address information.
Step7.) Now switch on router R3 and R2 and goto console of R1 and enter the following commands.
Note:- After entering the Ip information in the loopback interface just try pinging the ip address of loopback from the Router.
R1(config)#ip host R2 2001 192.168.1.3
R1(config)#ip host R3 2002 192.168.1.3
The command syntax is ip host <hostname> <telnet port> < ip address>
in our cases the host names are R1 and R2 , Telnet port are 2001 and 2002 ( Checked using step 4 of part2.) and ip address is of the loopback adapter.
Final Step.) Now to goto the R2 or R3 from the console of R1 exit the global conf mode and just type R2 or R3 and its done.
You have just configure access server on GNS3 🙂 if you have any problems setting this access server in your gn3 leave a reply.