Last Modified: Aug 19, 2026
Affected Product(s):
BIG-IP GTM, LTM
Known Affected Versions:
11.5.1, 11.5.1 hf1, 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, 11.5.1 hf10, 11.5.1 hf11, 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
Opened: Jul 07, 2015 Severity: 3-Major Related Article:
K16716213
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.
This can cause dns response failure.
The RTT for the nameserver cache reached the maximum value of 120000.
Change size for nameserver-cache-count to reset the nameserver cache. # tmsh modify /ltm dns cache resolver my_dns_cache nameserver-cache-count 16536
Maximum RTT value for nameserver cache is now deleted when the nameserver cache is deleted, which is correct behavior.