An error-disabled port is a switch port that the device administratively disables after a configured protection condition is triggered. The port stops forwarding data and, for PoE violations, stops transmitting power. section 10.1.2 section 13.2.3
Common protection conditions include:
- Power policing detects that a powered device exceeds its configured cutoff power. section 10.1.2
- DHCP Snooping rate limiting detects DHCP messages arriving faster than the configured packets-per-second limit. section 13.2.3
- Related protection features include BPDU Guard and port security. section 13.2.3
Manual recovery after DHCP rate limiting
Configure `ip dhcp snooping limit rate 1` on Gi0/2. When the threshold is exceeded, the switch logs the violation and places the interface in err-disable state. Disconnect or correct the offending device, then issue `shutdown` followed by `no shutdown`. Automatic recovery can be enabled with `errdisable recovery cause dhcp-rate-limit`. section 13.2.3
Verifying PoE protection
Use `power inline police` in interface configuration mode, then verify with `show power inline police`. The output displays administrative and operational policing states, cutoff power, and operating power. section 10.1.2
