Securing the edge with DHCP Snooping and Dynamic ARP Inspection (DAI) is critical, but recent lab validations on Catalyst 1300 firmware 4.1.3.36 reveal a specific protocol interoperability friction. When certain SIP endpoints aggressively issue ARP probes before the switch commits its DHCP binding database, DAI drops the packets, causing unpredictable DHCPDECLINE behaviors. In this independent lab debugging report, CCIE David Lorame breaks down the Wireshark PCAP evidence, CLI drop counters, and the verified MAC-based ARP ACL workaround needed to stabilize your telephony provisioning.
