Symptom

Unicast DHCP packets received by a Cisco ACI leaf switch will be redirected to the CPU and dropped, but the broadcast DHCP discover message will be forwarded to the DHCP server.

Conditions

1. DHCPv4. 2. DHCP Renew/Inform packets sent as unicast from client to DHCP server, source port 68 and destination port 67. 3. Client - DHCP relay on Gateway router - External Routed network (L3Out) or EPG in ACI - EPG with DHCP server topology.

Workaround

Contact TAC to modify the forwarding rules; this will fix the issue until the next reload.

Further Problem Description