Last Modified: Apr 28, 2025
Affected Product(s):
BIG-IP LTM
Known Affected Versions:
11.5.1, 11.5.1 HF1, 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, 11.5.1 HF10, 11.5.1 HF11, 11.5.2, 11.5.2 HF1, 11.5.3, 11.5.3 HF1, 11.5.3 HF2, 11.5.4, 11.5.4 HF1, 11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4, 11.6.0 HF5, 11.6.0 HF6, 11.6.0 HF7, 11.6.0 HF8
Fixed In:
12.0.0, 11.6.1, 11.5.4 HF2
Opened: Mar 18, 2015 Severity: 3-Major Related Article:
K76190485
Occasionally, ACK is sent to server without SYN, connection get RST.
Some connections will be dropped.
1) FastL4 virtual server. 2) Hardware syncookie enabled. 3) Might more commonly occur with forwarding virtual servers. 4) Often happens when egress router has ARP timeout.
Configure a static ARP to all neighbors (routers) to avoid most issues.
An issue with hardware syncookies and FastL4 connections has been resolved.