Last Modified: Apr 28, 2025
Affected Product(s):
BIG-IP LTM
Known Affected Versions:
11.5.1, 11.5.1 HF1, 11.5.1 HF2, 11.5.1 HF3, 11.5.1 HF4, 11.5.1 HF5, 11.5.1 HF6, 11.5.1 HF7, 11.5.1 HF8, 11.5.1 HF9, 11.5.1 HF10, 11.5.1 HF11, 11.5.2, 11.5.2 HF1, 11.5.3, 11.5.3 HF1, 11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4, 11.6.0 HF5
Fixed In:
12.0.0, 11.6.0 HF6, 11.5.3 HF2
Opened: Jan 22, 2015 Severity: 2-Critical Related Article:
K16457
The external monitoring daemon (bigd) sends monitoring traffic before tmm is ready to receive those responses. The response traffic is routed to a tmm on another blade/HA member. This tmm responds to the server with an ICMP "Unreachable" message. Meanwhile, the originating tmm on the new blade/HA member marks the pool member "down" because it never received the server's response.
Some packets are lost for several seconds. It can be longer depending on the total number of pool members.
Start with at least 1 blade enabled in a chassis or one HA member configured, and pass traffic constantly through a virtual server with a monitor-enabled pool attached. Then, enable a new blade in the cluster or a new HA member.
Before adding a new blade to a chassis or a member to the HA configuration that is actively processing traffic, temporarily remove the monitor(s) from the pool. Once the new blade/HA member is up, manually add the monitor(s) back to the pool.
When a VIPRION blade or BIG-IP HA member comes on-line, the bigd process on the blade/HA member no longer starts health monitors prematurely, which could have caused some monitored objects to be marked down incorrectly.
The external monitoring daemon (bigd) no longer sends monitoring traffic while the blade (cluster member) is offline or disabled, or while the HA member (chassis or appliance) is offline (including forced offline).