The Cisco router must be configured to advertise a hop limit of at least 32 in Router Advertisement messages for IPv6 stateless auto-configuration deployments.

The Neighbor Discovery protocol allows a hop limit value to be advertised by routers in a Router Advertisement message being used by hosts instead of the standardized default value. If a very small value was configured and advertised to hosts on the LAN segment, communications would fail due to the hop limit reaching zero before the packets sent by a host reached its destination.

Review the router configuration to determine if the hop limit has been configured for Router Advertisement messages as shown in the example.

ipv6 hop-limit 128

If it has been configured and has not been set to at least 32, it is a finding.

Configure the router to advertise a hop limit of at least 32 in Router Advertisement messages.

R1(config)#ipv6 hop-limit 128