Changing IP address via Telnet on a running router

[SgtZim]

Hi all,

I've got a situation where I have a remote router that I need to change the IP address on (we are changing ISP's). When I try to change the IP address of the interface, the change seems to take immediately and lock me out until the router is power cycled and comes back on the old IP. Is there a way I can set my changes to the startup config, then issue the command to reboot and have the router come back up on the new IP without locking myself out? I have to do this to two routers and it would be a huge help if I could do it from my home office.

 

[zzkarlzz]

You can make your changes in a text file, TFTP the file to the startup-config, then reload. You have to be VERY CAREFUL with this, since the only backout is through the console port. A reload is not going to help, since you have changed the startup config.

 

[Degg]

you could put the new IP address as a secondary IP, then it wouldnt disconnect you. then you could make other changes and when ready remove the old IP and make the new IP the primary one. I'm not sure if you could copy a config to the boot config (like from a tftp server), then reload the router and the new config has the new IP address.
What other changes need to be made? you can add in new static routes for the new IP, then when you change the IP and get disconnected, you can try the new IP to log in again.

D Degg
Network Administrator

 

[SgtZim]

Figured out my own problem.

What I did was set the IP of the new ISP as the secondary on the interface.
Made the rest of my changes.
Moved the physical network connection at the home office end to the new ISP.
Got back in and set the primary IP to the new one. Doing this automatically removes the secondary IP as they both cant be the same.
wr mem and done. All is well.