Bug ID 637227: DNS Validating Resolver produces inconsistent results with DNS64 configurations.

Last Modified: Oct 07, 2023

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

Known Affected Versions:
11.2.1, 11.5.0, 11.5.1, 11.5.2, 11.5.3, 11.5.4, 11.5.5, 11.5.6, 11.5.7, 11.5.8, 11.5.9, 11.5.10, 11.6.0, 11.6.1, 11.6.2, 11.6.3, 11.6.3.1, 11.6.3.2, 11.6.3.3, 11.6.3.4, 11.6.4, 11.6.5, 11.6.5.1, 11.6.5.2, 12.0.0, 12.0.0 HF1, 12.1.0 HF1, 12.0.0 HF2, 12.1.0 HF2, 12.0.0 HF3, 12.0.0 HF4, 12.1.1 HF1, 12.1.1 HF2, 12.1.2 HF1, 12.1.2 HF2, 12.1.0, 12.1.1, 12.1.2, 12.1.3, 12.1.3.1, 12.1.3.2, 12.1.3.3, 12.1.3.4, 12.1.3.5

Fixed In:
13.1.0, 13.0.0, 12.1.3.6, 11.6.5.3

Opened: Jan 06, 2017

Severity: 3-Major

Related Article: K60414305

Symptoms

A DNS Validating Resolver incorrectly validates DNS responses received from A queries made as a result of a front-end AAAA query received on a profile with DNS64 configured. A SERVFAIL response may be sent to the client unless the Validating Resolver cache has previously successfully validated a front-end A query. In this scenario where the A records already exist in the cache, the expected DNS64 AAAA records are synthesized.

Impact

Incorrect SERVFAIL responses for AAAA queries that should get valid responses.

Conditions

This issue may be observed with a DNS Validating Resolver configured on a DNS profile with DNS64 configured when processing AAAA queries.

Workaround

None.

Fix Information

DNS validation now occurs as expected, resulting in valid answers to AAAA queries.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips