Bug ID 739963: TLS v1.0 fallback can be triggered intermittently and fail with restrictive server setup

Last Modified: Sep 13, 2023

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

Known Affected Versions:
12.1.3,,,,,,,, 12.1.4,, 13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3, 13.0.1, 13.1.0,,,,,,,,, 13.1.1,,, 14.0.0,,,,,, 14.0.1, 14.1.0,

Fixed In:
15.0.0,,,, 12.1.5

Opened: Aug 10, 2018

Severity: 3-Major


HTTPS monitors mark a TLS v1.2-configured pool member down and never mark it back up again, even if the pool member is up. The monitor works normally until the SSL handshake fails for any reason. After the handshake fails, the monitor falls back to TLS v1.1, which the pool members reject, and the node remains marked down.


Once the handshake fails, the monitor remains in fallback mode and sends TLS v1.0 or TLS v1.1 requests to the pool member. The pool member remains marked down.


This might occur when the following conditions are met: -- Using HTTPS monitors. -- Pool members are configured to use TLS v1.2 only.


To restore the state of the member, remove it and add it back to the pool.

Fix Information


Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips