Symptom

Two IPv4 entries were learnt for the same MAC in device-tracking table, one from DHCP packet, another from ARP. "IPv4 Address" field in access-session showed "unknown" or the APIPA address (169.x), instead of the DHCP4 IP.

Conditions

"ip dhcp snooping vlan X" and LISP are enabled on the same vlan. In 16.6, as the result of the configuration, "DT_PROGRAMMATIC" device-tracking policy is attached to the vlan. DHCP packets are exchanged between a host and DHCP server/relay. => An DHCP4 entry is installed in device-tracking table. An ARP packet is received with target IP pointing to the APIPA (169.x) IP address of the host. =>An ARP entry is installed in device-tracking table with "UNKNOWN" state, mac address of 0000.0000.00fd. Multiple ARP packets are received with same target IP pointing to the APIPA (169.x) IP address of the host. An ARP Reply is received from from the host. => ARP entry is updated to "REACHABLE" state and the host mac address.

Workaround

no workaround.

Further Problem Description