Bug ID 876677: When running the debug version of TMM, an assertion may be triggered due to an expired DNS lookup.

Last Modified: Feb 07, 2024

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

Known Affected Versions:
15.1.0,,,,,, 15.1.1, 15.1.2,, 15.1.3,, 15.1.4,, 15.1.5,, 15.1.6, 16.1.0, 16.1.1, 16.1.2,

Fixed In:

Opened: Feb 04, 2020

Severity: 2-Critical


When running the debug version of TMM, if a particular DNS lookup takes more than 30 seconds, TMM may assert with a message in the /var/log/tmm file similar to the following example: notice panic: ../modules/hudfilter/3dns/cache_resolver.c:2343: Assertion "standalone refcnt must be one" failed.


TMM crashes and, in redundant configurations, the unit fails over.


-- Using the debug TMM -- Using the RESOLV::lookup iRule command -- The DNS server targeted by the aforementioned command is running slowly or malfunctioning


Do not use the debug TMM.

Fix Information

The debug assert was removed and replaced by a debug log.

Behavior Change

Guides & references

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