Details

The administrator must ensure that the maximum hop limit is at least 32.

The Neighbor Discovery protocol allows a hop limit value to be advertised by routers in a Router Advertisement message to be 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 hop limit reaching zero before the packets sent by a host reached its destination.

NOTE: The IOS default is 64. Hence, if the hop limit is not configured, the router will be in compliance with the requirement.

Solution

If the maximum hop limit is configured, it must be set to at least 32.

Supportive Information

The following resource is also helpful.

• https://iasecontent.disa.mil/stigs/zip/U_Network_Infrastructure_Router_L3_Switch_V8R29_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
• CSCv6|3.1
• Rule-ID|SV-40389r1_rule
• STIG-ID|NET-IPV6-059
• Vuln-ID|V-30617

Source

• Tenable.com/audits