Bug ID 571095: Monitor probing to pool member stops after FQDN pool member with same IP address is deleted

Last Modified: Sep 13, 2023

Affected Product(s):
BIG-IP LTM(all modules)

Known Affected Versions:
12.1.0, 12.1.1, 12.1.2, 12.1.3,,, 13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3, 13.0.1

Fixed In:

Opened: Feb 01, 2016

Severity: 3-Major


If an FQDN pool member resolves to the same IP address (node) as a non-FQDN (static) pool member, and the FQDN pool/member is deleted, no further monitor probes are sent to the remaining non-FQDN (static) pool member.


Loss of health monitoring to remaining non-FQDN (static) pool member.


This occurs if an FQDN pool member resolves to the same IP address (node) as an existing non-FQDN (static) pool member.


There is no workaround other than avoiding creating a static pool member with the same IP address that could be resolved to an FQDN name.

Fix Information

An FQDN pool member and static (non-FQDN) pool member can no longer be created with the same IP address, preventing loss of monitoring of the static member of the conflicting FQDN pool member is deleted. This issue is resolved by the FQDNv2 feature re-implementation in this version of the software.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips