Bug ID 438555: BIG-IP sometimes truncates large ICAP responses

Last Modified: Apr 28, 2025

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

Known Affected Versions:
11.3.0, 11.4.0, 11.4.1

Fixed In:
11.5.0, 11.4.1 HF6

Opened: Nov 20, 2013

Severity: 2-Critical

Related Article: K15634

Symptoms

BIG-IP may sometimes truncate large ICAP response streams returning from the ICAP server, even after the complete request has gone out to the ICAP server. This occurs after the fix for bug 429994 has been applied. The TCP window will slowly close, and might open and close a few times (normal flow-control) but at some point might close and never open.

Impact

Large files returning from an ICAP server may be truncated.

Conditions

Fix for bug 429994 has been applied. Request-adapt or response-adapt, and icap profile. Large ICAP response stream (such as file get or post). Conditions are such that flow-control is operating.

Workaround

Avoid flow-control conditions.

Fix Information

Flow returning from ICAP server see TCP window operating normally and does not lock up.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips