Bug ID 2223645: BIG-IP does not implement traffic forwarding as per RFC 3927

Last Modified: Apr 23, 2026

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

Known Affected Versions:
17.1.0, 17.1.0.1, 17.1.0.2, 17.1.0.3, 17.1.1, 17.1.1.1, 17.1.1.2, 17.1.1.3, 17.1.1.4, 17.1.2, 17.1.2.1, 17.1.2.2, 17.1.3, 17.1.3.1, 17.5.0, 17.5.1, 17.5.1.2, 17.5.1.3, 17.5.1.4, 17.5.1.5, 21.0.0, 21.0.0.1

Opened: Feb 13, 2026

Severity: 3-Major

Symptoms

BIG-IP does not implement traffic forwarding as per RFC 3927#section-7 Routers must not forward packets with an IPv4 link-local source or destination address, regardless of routing configuration.

Impact

Incorrect traffic forwarding.

Conditions

BIG-IP acting as a proxy for Ipv4 traffic.

Workaround

Create an iRule to drop traffic to or from specific addresses.

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips