Bug ID 557667: Some monitor types may fail to probe when the monitor definition is changed

Last Modified: Sep 13, 2023

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

Known Affected Versions:
11.6.1, 11.6.2, 12.0.0, 12.0.0 HF1, 12.1.0 HF1, 12.0.0 HF2, 12.1.0 HF2, 12.0.0 HF3, 12.0.0 HF4, 12.1.1 HF1, 12.1.1 HF2, 12.1.2 HF1, 12.1.2 HF2

Fixed In:
12.1.0, 11.6.3

Opened: Nov 11, 2015

Severity: 3-Major

Related Article: K73162091


The BIG-IP system may fail to send monitor probes for FTP, IMAP, POP3, or SMTP monitors for monitored objects (pool member or nodes) after the configuration of the monitor is updated.


Pool member or node status may no longer be updated and the BIG-IP system no longer properly tracks the health of the monitored object.


FTP, IMAP, POP3, or SMTP monitors are configured and a change is made to the monitor definition while the monitor is assigned to a pool member or node. The problem is more likely to occur if the monitor probe takes a long time to complete.


To mitigate this issue, avoid making changes to FTP, IMAP, POP3, or SMTP monitor definitions.

Fix Information

Altering the configuration of an FTP, IMAP, POP3, or SMTP monitor no longer causes the BIG-IP system to stop monitoring the object.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips