Bug ID 890229: Source port preserve setting is not honoured

Last Modified: Jun 03, 2020

Bug Tracker

Affected Product:  See more info
BIG-IP LTM(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, 13.1.1.1, 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, 14.0.0, 14.0.0.1, 14.0.0.2, 14.0.0.3, 14.0.0.4, 14.0.0.5, 14.0.1, 14.0.1.1, 14.1.0, 14.1.0.1, 14.1.0.2, 14.1.0.3, 14.1.0.4, 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, 15.0.0, 15.0.1, 15.0.1.1, 15.0.1.2, 15.0.1.3, 15.1.0, 15.1.0.1, 15.1.0.2, 15.1.0.3

Opened: Mar 16, 2020
Severity: 3-Major

Symptoms

The source port is always changed in source-port preserve mode even if the original source port with the other parameters would hash to the same TMM.

Impact

Applications relying on a specific, fixed source port might not work as expected.

Conditions

This issue occurs when all of the following conditions are met: -- You have configured a hash that includes IP addresses, which you can accomplish in any of the following ways: + Using RSS DAG as a default hash on BIG-IP Virtual Edition (VE) (Z100) or on 2000- and 4000-series devices. + By configuring a VLAN's 'CMP Hash' setting to a non-default value. + By using a special variable like udp.hash or tcp.hash. -- The virtual server is configured with source-port preserve (the default).

Workaround

Set source-port to preserve-strict.

Fix Information

None

Behavior Change

Beginning with v16.0.0, the TM.PortFind.Src_Preserve BigDB variable introduced in v15.1.0 is no longer supported. The source-port preserve setting now does best effort to preserve the source port.