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Port stops passing traffic, shows D-down under show port status, shows testing status on NMS

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TitlePort stops passing traffic, shows D-down under show port status, shows testing status on NMS
Symptoms
Port stops passing traffic until reset.
Environment
EOS/Wireless
Cause
DHCP snooping enabled on a port with an AP plugged into it. The cause of this behavior is DHCP REQ/OFFER/NAK/DHCP ACK/DHCP/NAK packets ingressing these ports at a rate faster than the configured threshold. DHCP Snooping's Rate Limiting behavior examines each untrusted port for received DHCP packets exceeding a configurable rate per burst interval (by default, 15 packets per second). If the receive rate exceeds the limit, DHCP Snooping brings down the port, and the ports admin status is listed as D-Down. The testing port status is due to the action of the Object ifAdminStatus MIB:

Object ifAdminStatus
OID 1.3.6.1.2.1.2.2.1.7
Type INTEGER
Permission read-write
Status current
Values

1 : up
2 : down
3 : testing

Description "The desired state of the interface. The testing(3) state
indicates that no operational packets can be passed. When a
managed system initializes, all interfaces start with
ifAdminStatus in the down(2) state. As a result of either
explicit management action or per configuration information
retained by the managed system, ifAdminStatus is then
changed to either the up(1) or testing(3) states (or remains
in the down(2) state)."
 
Resolution
The fix here is simple, as these are AP ports, that should be servicing DHCP requests for attached clients the command:

Set dhcpsnooping trust port <port_string> enable

Should be run on all ports with APs plugged into them. This command should also be run on the uplink if DHCPsnooping is enabled there as well.
Additional notes

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