Bug ID 514726: Server-side DSR tunnel flow never expires

Last Modified: Oct 06, 2020

Bug Tracker

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

Known Affected Versions:
11.4.0, 11.4.1, 11.5.0, 11.5.1, 11.5.1 HF1, 11.5.1 HF10, 11.5.1 HF11, 11.5.1 HF2, 11.5.1 HF3, 11.5.1 HF4, 11.5.1 HF5, 11.5.1 HF6, 11.5.1 HF7, 11.5.1 HF8, 11.5.1 HF9, 11.5.10, 11.5.2, 11.5.2 HF1, 11.5.3, 11.5.3 HF1, 11.5.3 HF2, 11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4, 11.6.0 HF5

Fixed In:
12.0.0, 11.6.0 HF6, 11.5.4, 11.4.1 HF9

Opened: Mar 26, 2015
Severity: 3-Major
Related AskF5 Article:


TMM cores and memory exhaustion using Direct Server Return (DSR). DSR establishes a one-way tunnel between the BIG-IP system and the back-end servers using the clients' IP addresses as the tunnel local-address on the BIG-IP system. These flows never expire.


Server-side DSR tunnel flow never expires. Because the DSR tunnels use client's IP address as the tunnel local-address and the server's IP address as the tunnel remote-address, a single DSR setup might introduce as many tunnels as the clients' requests. When these tunnels do not expire, the BIG-IP system memory resource might be used up eventually, causing TMM cores. Traffic disrupted while tmm restarts.


BIG-IP virtual servers using DSR tunnels to send client traffic to the server.



Fix Information

Individual DSR tunnels are removed after the corresponding client's user flows expire.

Behavior Change