Bug ID 1617289: ZebOS can advertise a route with a nexthop of 0.0.0.0 if the interface lookup fails.

Last Modified: Oct 19, 2025

Affected Product(s):
BIG_IP_NEXT(SPK) SPK(all modules)

Fixed In:
1.7.10

Opened: Jul 18, 2024

Severity: 2-Critical

Symptoms

ZebOS can advertise a route with a nexthop of 0.0.0.0 if the interface lookup fails. This lookup may fail in certain rare circumstances triggered by a TMM restart.

Impact

Traffic will not be routed properly on the peer router that received the route.

Conditions

Occurred when a network interface lookup by IPv4 address failed, and no suitable interface was found.

Workaround

Restarting the pod will fix the advertised route.

Fix Information

In the ZebOS codebase, the IPv4 nexthop is now assigned a default value instead of being initialized to zero. If an interface lookup fails, it will now use the default value instead of zero. Additional logging was added in case the nexthop is 0.0.0.0 again.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips