Bug ID 636633: DHCP: DHCP PEM sessions are not cleared (until idle timeout) after IP release from client in some cases

Last Modified: Apr 19, 2021

Bug Tracker

Affected Product:  See more info
BIG-IP PEM(all modules)

Known Affected Versions:
11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4, 11.6.0 HF5, 11.6.0 HF6, 11.6.0 HF7, 11.6.0 HF8, 11.6.1, 11.6.1 HF1, 11.6.1 HF2, 11.6.2, 11.6.2 HF1, 11.6.3,,,,, 11.6.4, 11.6.5,,,, 12.0.0, 12.0.0 HF1, 12.0.0 HF2, 12.0.0 HF3, 12.0.0 HF4, 12.1.0, 12.1.0 HF1, 12.1.0 HF2, 12.1.1, 12.1.1 HF1, 12.1.1 HF2, 12.1.2, 12.1.2 HF1, 12.1.2 HF2, 12.1.3,,,,,,,, 12.1.4,, 12.1.5,,,, 12.1.6, 13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3, 13.0.1

Fixed In:

Opened: Jan 04, 2017
Severity: 3-Major


In some scenarios, DHCP IP release messages received by BIG-IP do not trigger corresponding PEM sessions to be removed from sessionDB. These sessions will removed after timeout.


Session deletion will not happen immediately. Note: The client does not typically send DHCP release, so the chance of this occurring in real-world environments is small.


1. Run DHCP DORA process to create PEM sessions via DHCP (relay or forwarding mode). 2. Wait for some time (1-2 minutes). 3. Send DHCP renewal message to the BIG-IP system. 4. Send DHCP release message to the BIG-IP system. 5. Check sessionDB to see if the corresponding PEM session is deleted. The problem happens only if the DHCP renewal/release does not arrive at the tmm where sessionDB is located.


You can use either of the following workarounds: -- Delete PEM session manually. -- Wait for PEM session to timeout

Fix Information

The system now removes PEM session from sessionDB regardless which tmm DHCP IP release is received. This is correct behavior.

Behavior Change