Bug ID 919553: GTM/DNS monitors based on the TCP protocol may fail to mark a service up when the server's response spans multiple packets.

Last Modified: Nov 07, 2022

Bug Tracker

Affected Product:  See more info
BIG-IP DNS, 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, 13.1.1.2, 13.1.1.3, 13.1.1.4, 13.1.1.5, 13.1.3, 13.1.3.1, 13.1.3.2, 13.1.3.3, 13.1.3.4, 14.1.0, 14.1.0.1, 14.1.0.2, 14.1.0.3, 14.1.0.5, 14.1.0.6, 14.1.2, 14.1.2.1, 14.1.2.2, 14.1.2.3, 14.1.2.4, 14.1.2.5, 14.1.2.6, 14.1.2.7, 14.1.2.8, 14.1.3, 15.1.0, 15.1.0.1, 15.1.0.2, 15.1.0.3, 15.1.0.4, 15.1.0.5, 16.0.0, 16.0.0.1

Fixed In:
16.1.0, 16.0.1, 15.1.1, 14.1.3.1, 13.1.3.5

Opened: Jun 19, 2020
Severity: 2-Critical

Symptoms

GTM/DNS monitors based on the TCP protocol may fail to find the configured receive string in the server's response, causing the monitored service to be incorrectly marked down.

Impact

A service is incorrectly marked down. This can cause the BIG-IP GTM/DNS to return a suboptimal answer or no answer at all to DNS queries.

Conditions

This issue occurs when the server's response spans multiple packets (for example, when the response is particularly large or includes dynamically generated content delivered in chunks).

Workaround

This issue can be worked around by ensuring your server returns a response to the BIG-IP GTM/DNS's monitor that fits in one packet.

Fix Information

GTM/DNS monitors based on the TCP protocol no longer fail when the server's response spans multiple packets.

Behavior Change