Came across a post online that I thought would help those who have been through the problem and upset of losing VLAN configurations once a router in GNS3 or Dynamips is reloaded. This post explains how to prevent this from happening.

ok, when you restart your Router or you turn off the GNS3, the VLAN configuration is missing, why? Because all the VLAN information is save to file vlan.dat. Yes, you know that already.

So, this is the step to save the configuration :

K-ROUTER#erase flash
Erasing the flash filesystem will remove all files! Continue? [confirm]
Erasing device… eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee …erased
Erase of flash: complete

K-ROUTER#squeeze flash:
Squeeze operation may take a while. Continue? [confirm]
squeeze in progress…
Squeeze of flash complete

K-ROUTER#conf t
Enter configuration commands, one per line. End with CNTL/Z.
K-ROUTER(config)#vtp file nvram:vlan.dat
Setting device to store VLAN database at filename nvram:vlan.dat.

K-ROUTER(config)#do dir nvram:
Directory of nvram:/

124 -rw- 0 startup-config
125 —- 0 private-config
1 -rw- 600 vlan.dat

129016 bytes total (127940 bytes free)
K-ROUTER(config)#

K-ROUTER(config)#do wr mem
Building configuration…
[OK]

ok, after that you can configure your vlan, vtp without worrying will lost the information.

Credit to the original blog where I found this: GNS3 : Saving VLAN Information

Enjoy ..

LBS

Tags: GNS3 Tips, VLAN