Bug ID 757775: Added DB variable to force setting RA bit in response from cache

Last Modified: Feb 20, 2020

Bug Tracker

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

Known Affected Versions:
13.1.0, 13.1.0.1, 13.1.0.2, 13.1.0.3, 13.1.0.4, 13.1.0.5, 13.1.0.6, 13.1.0.7, 13.1.0.8, 13.1.1, 13.1.1.1, 13.1.1.2, 13.1.1.3, 13.1.1.4, 13.1.1.5, 13.1.3, 13.1.3.1, 13.1.3.2, 14.0.0, 14.0.0.1, 14.0.0.2, 14.0.0.3, 14.0.0.4, 14.0.0.5, 14.0.1, 14.0.1.1, 14.1.0, 14.1.0.1, 14.1.0.2, 14.1.0.3, 14.1.0.4, 14.1.0.5, 14.1.0.6, 14.1.2, 14.1.2.1, 14.1.2.2, 14.1.2.3, 15.0.0, 15.0.1, 15.0.1.1, 15.0.1.2

Fixed In:
15.1.0

Opened: Feb 06, 2019
Severity: 3-Major

Symptoms

Under certain conditions, a response from Transparent cache may not have the RA (Recursion Available) bit set.

Impact

A response from Transparent cache does not have RA bit set.

Conditions

The issue takes place under the following conditions: -- Response going from a transparent cache. -- The msg sub-cache does not contain the query. -- The rrset sub-cache does contain the query.

Workaround

The following iRule resolves the issue: When DNS_RESPONSE { DNS::header ra 1 }

Fix Information

Added new DB variable dnscache.forcerecursionavailablebit which, when enabled, forces setting the RA bit in responses coming from any type of cache.

Behavior Change