Bug ID 1302825: Allow configuration of the number of times the CNAME chase is performed

Last Modified: May 29, 2024

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

Known Affected Versions:
15.1.0, 15.1.0.1, 15.1.0.2, 15.1.0.3, 15.1.0.4, 15.1.0.5, 15.1.1, 15.1.2, 15.1.2.1, 15.1.3, 15.1.3.1, 15.1.4, 15.1.4.1, 15.1.5, 15.1.5.1, 15.1.6, 15.1.6.1, 15.1.7, 15.1.8, 15.1.8.1, 15.1.8.2, 15.1.9, 15.1.9.1, 15.1.10, 15.1.10.2, 15.1.10.3, 15.1.10.4, 16.1.0, 16.1.1, 16.1.2, 16.1.2.1, 16.1.2.2, 16.1.3, 16.1.3.1, 16.1.3.2, 16.1.3.3, 16.1.3.4, 16.1.3.5, 16.1.4, 16.1.4.1, 16.1.4.2, 16.1.4.3, 17.1.0, 17.1.0.1, 17.1.0.2, 17.1.0.3

Fixed In:
17.1.1

Opened: May 29, 2023

Severity: 3-Major

Symptoms

The client receives a SERVFAIL when the CNAME queried to the BIG-IP DNS resolver takes more than the limit configured in the DNS Cache. The limit is set as 11 for BIG-IP v17.1.0 and later. It is fixed as 8 for earlier releases.

Impact

The clients cannot resolve DNS names if the count of the CNAME chases goes beyond the limit configured in the DNS cache.

Conditions

A BIG-IP DNS is configured as a resolver (as a cache or a net resolver). The domain of which CNAME resolution is asked requires chasing more times than what is pre-configured in the DNS Cache.

Workaround

The providers whose CNAME is queried can be asked to keep chains shorter than the pre-configured limits (the limits vary between different versions of BIG-IP).

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips