Details

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.

Solution

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

R1(config)#ipv6 hop-limit 128

Supportive Information

The following resource is also helpful.

• https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Cisco_IOS-XE_Router_Y21M10_STIG.zip

This security hardening control applies to the following category of controls within NIST 800-53: Configuration Management.This control applies to the following type of system Cisco.

References

• 800-53|CM-6b.
• CAT|III
• CCI|CCI-000366
• CSCv6|3.1
• Rule-ID|SV-230039r647454_rule
• STIG-ID|CISC-RT-000236
• Vuln-ID|V-230039

Source

• Tenable.com/audits