Symptom
DHCP stops working through the fabric after upgrade to 2.1.2e/12.1.2e
Conditions
DHCP relayed frames received on an L2-only Bridge Domain (BD) are dropped by the leaf. This bug does not affect DHCP discover/offers from the server or client. It only affects the DHCP relayed frames (where both source and destination port are 67 in the UDP header)
- DHCP through the fabric.
-L2 BD
-DHCP relay NOT configured in the fabric (external relay)
-2.1.2e
Workaround
1) Add a link to the DHCP server within the same BD of the affected clients
2) Enable unicast routing on the affected BD, add an appropriate subnet, and add DHCP relay configuration to the ACI fabric. Ensure that 'enforce subnet check' is enabled on the BD
3) If DHCP relay is not configured under BD on the leaf (as verified via 'show ip dhcp relay'), then TAC can assist in temporarily disabling the hardware rule that is redirecting the affected DHCP traffic. This workaround should only be applied as a temporary measure until one of the above workarounds can be implemented, or until the switch can be upgraded/downgraded to an unaffected version of code.
