I am running 2 x Cisco 2951 routers and had an issue when I shut down gi0/1 on one router - the same interface on another router on the same subnet, would shut.
I had HSRP configured and assumed that this may be causing the problems. I removed all HSRP config from both routers, reloaded them, but the problem still persisted. Same issue with Stateful NAT, removed that, problem still exists.
I note I have a config line that simply says - redundancy, but cannot modify or remove this line.
What other aspects should I be looking at here?