The Cisco switch must be configured to advertise a hop limit of at least 32 in Switch Advertisement messages for IPv6 stateless auto-configuration deployments.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| low | V-237751 | SRG-NET-000512-RTR-000012 | CISC-RT-000236 | SV-237751r648779_rule | 2024-06-06 | 3 |
| Description |
|---|
| 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. |
| ℹ️ Check |
|---|
| Review the switch configuration to determine if the hop limit has been configured for Router Advertisement messages as shown in the example. ipv6 hop-limit 128 If hop-limit has been configured and has not been set to at least 32, it is a finding. |
| ✔️ Fix |
|---|
| Configure the switch to advertise a hop limit of at least 32 in Router Advertisement messages as shown in the example. SW1(config)#ipv6 hop-limit 128 |