Bug ID 653511: Intermittent connection failure with SNAT/automap, SP-DAG and virtual server source-port=preserve

Last Modified: Oct 06, 2020

Bug Tracker

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

Known Affected Versions:
12.0.0, 12.0.0 HF1, 12.0.0 HF2, 12.0.0 HF3, 12.0.0 HF4, 12.1.0, 12.1.0 HF1, 12.1.0 HF2, 12.1.1, 12.1.1 HF1, 12.1.1 HF2, 12.1.2, 12.1.2 HF1, 12.1.2 HF2, 13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3

Fixed In:
13.1.0, 13.0.1, 12.1.3

Opened: Mar 25, 2017
Severity: 3-Major
Related AskF5 Article:


Connections can fail intermittently when multiple clients use the same ephemeral port to connect to BIG-IP and are SNATted to the same address.


Service interruption due to intermittent connection failures.


When SNAT/Automap is configured with SP-DAG and virtual server source-port setting is "preserve".



Fix Information

Connections no longer fail intermittently with SNAT/automap, SP-DAG and virtual server source-port=preserve.

Behavior Change