Bug ID 1538285: BIG-IP splits the PUBLISH message when an MQTT profile is applied

Last Modified: Jan 09, 2025

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

Known Affected Versions:
15.1.0, 15.1.0.1, 15.1.0.2, 15.1.0.3, 15.1.0.4, 15.1.0.5, 15.1.1, 15.1.2, 15.1.2.1, 15.1.3, 15.1.3.1, 15.1.4, 15.1.4.1, 15.1.5, 15.1.5.1, 15.1.6, 15.1.6.1, 15.1.7, 15.1.8, 15.1.8.1, 15.1.8.2, 15.1.9, 15.1.9.1, 15.1.10, 15.1.10.2, 15.1.10.3, 15.1.10.4, 15.1.10.5, 15.1.10.6, 16.1.0, 16.1.1, 16.1.2, 16.1.2.1, 16.1.2.2, 16.1.3, 16.1.3.1, 16.1.3.2, 16.1.3.3, 16.1.3.4, 16.1.3.5, 16.1.4, 16.1.4.1, 16.1.4.2, 16.1.4.3, 16.1.5, 16.1.5.1, 16.1.5.2, 17.1.0, 17.1.0.1, 17.1.0.2, 17.1.0.3, 17.1.1, 17.1.1.1, 17.1.1.2, 17.1.1.3, 17.1.1.4

Fixed In:
17.1.2

Opened: Feb 15, 2024

Severity: 4-Minor

Symptoms

When the PUBLISH message is sent from a client, the BIG-IP system splits the message and forwards it in two packets down the chain.

Impact

MQTT messages can be difficult to read due to fragmentation and poor reorganization by some applications.

Conditions

Basic Virtual Server with MQTT profile applied.

Workaround

None

Fix Information

Reunite split messages and forward them without fragmentation.

Behavior Change

A fix for the bug introduced behavior change, resulting in sending out an MQTT message header with payload (when it is expected) on the server side. 1) This fix works for _any_ MQTT message with a payload. 2) It would delay the egress of the message header until the first chunk of a payload is ready to egress (when a payload is expected for the message). 3) When no payload is expected, the message is immediately egressing.

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips