Bug ID 527387: Timeout config settings can result in incorrect monitoring

Last Modified: Apr 10, 2019

Bug Tracker

Affected Product:  See more info
BIG-IP TMOS(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

Fixed In:
12.0.0, 11.6.3

Opened: Jun 10, 2015
Severity: 3-Major
Related AskF5 Article:
K06611108

Symptoms

Pool members may not be marked correctly. They may be marked UP when they should be DOWN, or vice versa.

Impact

GTM may not notice that the monitored Pool Member is DOWN, and will leave it marked UP. Pool Members may be erroneously marked UP and used as answers in DNS Responses thus directing clients to unreachable nodes.

Conditions

If a monitor is configured with a timeout that is less than the interval, such as: gtm monitor external /Common/sample-timeout { defaults-from /Common/external destination *:* interval 10 probe-timeout 22 run /Common/sample_monitor timeout 5 }

Workaround

Configure monitors with a timeout value that is greater than the interval value.

Fix Information

Fixed an issue where Pool Member health is marked incorrectly.

Behavior Change