Bug ID 532107: [LTM] [DNS] Maximum RTT value for nameserver cache still exists after nameserver cache is deleted

Last Modified: Nov 07, 2022

Bug Tracker

Affected Product:  See more info
BIG-IP GTM, LTM(all modules)

Known Affected Versions:
11.4.1, 11.5.0, 11.5.1, 11.5.1 HF1, 11.5.1 HF10, 11.5.1 HF11, 11.5.1 HF2, 11.5.1 HF3, 11.5.1 HF4, 11.5.1 HF5, 11.5.1 HF6, 11.5.1 HF7, 11.5.1 HF8, 11.5.1 HF9, 11.5.10, 11.5.2, 11.5.2 HF1, 11.5.3, 11.5.3 HF1, 11.5.3 HF2, 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

Fixed In:
12.0.0, 11.6.1, 11.5.4, 11.4.1 HF10

Opened: Jul 07, 2015
Severity: 3-Major
Related Article:
K16716213

Symptoms

If RTT value for nameserver cache reached the maximum value as 120000, even after executing 'delete ltm dns cache nameserver', BIG-IP still keeps the past maximum RTT value.

Impact

This can cause dns response failure.

Conditions

The RTT for the nameserver cache reached the maximum value of 120000.

Workaround

Change size for nameserver-cache-count to reset the nameserver cache. # tmsh modify /ltm dns cache resolver my_dns_cache nameserver-cache-count 16536

Fix Information

Maximum RTT value for nameserver cache is now deleted when the nameserver cache is deleted, which is correct behavior.

Behavior Change