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

Last Modified: Aug 19, 2026

Affected Product(s):
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 Article: K45770397

Symptoms

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

Impact

Service interruption due to intermittent connection failures.

Conditions

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

Workaround

None.

Fix Information

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

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips