APM-DHCP Access Policy Example and Detailed Instructions

The DHCP RELEASE message will be sent the next time a user gets a DHCP address from that DHCP server. If the APM device is not busy you may see several RELEASE messages sent seriatim when a new session begins.

The DHCP iRule sends RELEASE messages as UDP "responses" to messages from the DHCP server so that the source and destination ports will be correct. The BIG-IP traffic disaggregator (DAG) only allows one of the TMM instances to send messages to any particular DHCP server with correct source and destination ports. Because an APM session may be attached to any of the TMM instances, when any session ends its RELEASE message is simply queued until the TMM selected by the DAG gets a packet flow going with the proper DHCP server. That DAG-favored TMM instance then sends all of the RELEASE messages queued for that DHCP server.