Bug ID 742078: Incoming SYNs are dropped and the connection does not time out.

Last Modified: May 29, 2024

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

Known Affected Versions:
14.1.0, 14.0.0, 13.1.1, 13.1.0, 13.0.1, 13.0.0, 12.1.4, 12.1.3, 11.6.3, 11.5.9, 11.5.8, 11.5.7, 11.5.6, 11.5.5

Fixed In:
15.0.0, 14.1.0.6, 14.0.0.5, 13.1.1.5, 12.1.4.1, 11.6.5.1

Opened: Aug 29, 2018

Severity: 3-Major

Symptoms

There is a hard-coded limit on the number of SYNs forwarded on a FastL4 connection. This might cause a problem when a connection is reused, for example, if a connection is not correctly closed.

Impact

If the number of SYNs on a single connection reaches this limit, subsequent incoming SYNs are dropped and the connection might not time out.

Conditions

-- SYN forwarding on FastL4 connections. -- The number of SYNs on a single connection reaches the hard-coded limit.

Workaround

There is no workaround.

Fix Information

The following command enables the forwarding of an an unlimited number of SYNs: tmsh modify sys db tm.dupsynenforce value disable

Behavior Change

Guides & references

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