Bug ID 918169: The GTM/DNS HTTPS monitor may fail to mark a service up when the SSL session undergoes an unclean shutdown.

Last Modified: Nov 07, 2022

Bug Tracker

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

Known Affected Versions:
13.1.0,,,,,,,,, 13.1.1,,,,, 13.1.3,,,,,, 14.0.0,,,,,, 14.0.1,, 14.1.0,,,,,, 14.1.2,,,,,,, 15.0.0, 15.0.1,,,,, 15.1.0,,,,,, 15.1.1, 16.0.0,, 16.0.1

Fixed In:
16.1.0,, 15.1.2,,

Opened: Jun 16, 2020
Severity: 2-Critical


The GTM/DNS HTTPS monitor may fail to find the configured receive string in a HTTP response, causing the monitored service to be incorrectly marked down.


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.


This issue occurs when all of the following conditions are true: -- The server being monitored performs an unclean shutdown of the SSL session (the underlying TCP connection is closed without first issuing a close notify alert at the SSL level). -- The server's HTTP response does not terminate with a newline.


This issue can be worked around by performing any one of the following actions: -- Ensure the server issues a close notify alert before it closes the underlying TCP connection. -- Ensure the server's HTTP response ends with a newline.

Fix Information

The GTM/DNS HTTPS monitor no longer fails when the SSL peer performs an unclean shutdown.

Behavior Change