Bug ID 803809: SIP messages fail to forward in MRF SIP when preserve-strict source port is enabled.

Last Modified: May 29, 2024

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

Known Affected Versions:
13.1.0,,,,,,,,, 13.1.1,,,,, 13.1.3,,,, 14.0.0,,,,,, 14.0.1,, 14.1.0,,,,,, 14.1.2,,,,,,, 15.0.0, 15.0.1,,,,, 15.1.0,

Fixed In:

Opened: Jul 10, 2019

Severity: 3-Major


When MRF SIP is configured in per-client mode and preserve-strict source port is enabled on a virtual server, messages may fail to forward due to port collisions when multiple clients try to use the same port (which is expected/accepted behavior with this configuration). After the port has been freed or the configuration changed, messages continue to fail for clients that had previous port collisions.


Calls from one or more clients are unable to be completed.


-- MRF SIP configured with: Per-Client connection mode and virtual server with preserve-strict source port enabled. -- Multiple clients try to connect using the same local port. -- Previously failed client connections attempt to connect again after the port has been freed or configuration changed.


You can prevent this behavior using either workaround: -- Configure a different connection mode (Per-TMM, for example). -- Disable preserve-strict source port on the virtual server.

Fix Information

Clients with previous connection failures are now able to connect when the port is no longer in use or the configuration has been changed.

Behavior Change

Guides & references

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