The default configuration for a Cisco switch is to have the errdisable configuration disabled. The feature of errdisable and recovery is fantastic and if used in conjunction with bpduguard will save you a serious amount of time roaming around a large area due to the incompetence of those you offer service to. I know we’ve all seen it, the helpful receptionist who plugs the other end of the CAT5e cable into the wall socket because it’s dangling down. ARGHHHHHH!!!! $^&%£ $%&&@$%…

You know where I’m coming from. Anyway, the point I’m trying to raise is that if you use bpduguard one of the edge ports will automatically become blocked by spanning-tree. You may not think it, but that is a good thing, no loop and your LAN/WAN is not detrimentally impacted. In an effort to save you a 50 mile drive to re-enable the port (just in case you don’t have remote access), you can use the errdisable feature. I tend to use this globally and as an example:

# show errdisable recovery

ErrDisable Reason Timer Status

—————– ————–

arp-inspection Disabled

bpduguard Disabled

inline-power Disabled

link-flap Disabled

# errdisable recovery cause bpduguard

# errdisable recovery interval 300

I personally tend to apply recovery against the link-flap, bpduguard and inline-power (it’s amazing how a user rebooting an IP phone can take down a port and errdisable it).


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