Bug ID 755727: Ephemeral pool members not created after DNS flap and address record changes

Last Modified: Sep 13, 2023

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

Known Affected Versions:
12.1.3,,,,,,,, 12.1.4,, 12.1.5,, 13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3, 13.0.1, 13.1.0,,,,,,,,, 13.1.1,,,,, 13.1.3,, 14.0.0,,,,,, 14.0.1,, 14.1.0,,,,,, 14.1.2,,,,, 15.0.0, 15.0.1,,

Fixed In:

Opened: Jan 17, 2019

Severity: 3-Major


When using FQDN node/pool members, ephemeral pool members may not be created for one or more pools after address records change on the DNS server. Once this condition occurs, ephemeral pool members are no longer created for a given FQDN name in the affected pool.


When this issue occurs, the affected pool may be left with no active pool members. In that case, virtual servers targeting the affected pool become unavailable and stop passing traffic.


This issue may occur under rare timing conditions when the following factors are present: -- Using FQDN nodes/pool members. -- Changes occur in the address records on the DNS server, causing new ephemeral nodes/pool members to be created and old ephemeral nodes/pool members to be deleted. -- There is a temporary loss of connectivity to/responsiveness from the DNS server.


When this issue occurs, the ability to create ephemeral pool members can be restored by either of the following actions: 1. Restart the dynconfd daemon: bigstart restart dynconfd 2. Delete and re-create the FQDN template pool member using the following two commands: tmsh mod ltm pool affected_pool members del { fqdn_pool_member:port } tmsh mod ltm pool affected_pool members add { fqdn_pool_member:port { additional field values } } To ensure that a pool contains active members even if this issue occurs, populate each pool with more than one FQDN pool member, or with an additional non-FQDN pool member.

Fix Information


Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips