Bug ID 778365: dns-dot & dns-rev metrics collection set RTT values even though LDNS has no DNS service

Last Modified: Dec 13, 2019

Bug Tracker

Affected Product:  See more info
BIG-IP TMOS(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, 15.0.0, 15.0.1

Fixed In:
15.1.0

Opened: Apr 30, 2019
Severity: 3-Major

Symptoms

DNS-DOT or DNS-REV protocols are used to collect RTT metrics on the LDNS. If there is DNS service running on the LDNS, RTT metrics should be collected successfully as expected. However if there is no DNS service on the LDNS, there should not be any RTT metrics collected. But BIG-IP still populates the RTT values giving users a "false positive" results.

Impact

RTT metrics are collected even though no response from the DNS service is present giving users wrong impression that there is.

Conditions

DNS-DOT or DNS-REV protocols are used to collect RTT metrics on the LDNS and there is no DNS service running on the LDNS.

Workaround

None

Fix Information

RTT metrics are collected only when the DNS service is present otherwise zero RTT values are returned.

Behavior Change