Hop-Limit - Cisco Nexus 7000 Series Command Reference Manual

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hop-limit

To verify the advertised hop-count limit, use the hop-limit command in RA guard policy configuration mode.

hop-limit {maximum| minimum } limit

Syntax Description

maximum limit

minimum limit

Command Default

No hop-count limit is specified.

Command Modes

RA guard policy configuration (config-ra-guard)

Command History

Usage Guidelines

The hop-limit command enables verification that the advertised hop-count limit is greater than or less than

the value set by the limit argument. Configuring the minimum limit keyword and argument can prevent an

attacker from setting a low hop-count limit value on the hosts to block them from generating traffic to remote

destinations; that is, beyond their default router. If the advertised hop-count limit value is unspecified (which

is the same as setting a value of 0), the packet is dropped.

Configuring the maximum limit keyword and argument enables verification that the advertised hop-count

limit is lower than the value set by the limit argument. If the advertised hop-count limit value is unspecified

(which is the same as setting a value of 0), the packet is dropped.

The following example shows how the command defines a router advertisement (RA) guard policy name as

raguard1, places the router in RA guard policy configuration mode, and sets a minimum hop-count limit of

switch(config)# ipv6 nd raguard policy raguard1

switch(config-ra-guard)# hop-limit minimum 3

Cisco Nexus 7000 Series Security Command Reference

Verifies that the hop-count limit is lower than that set

by the limit argument.

Verifies that the hop-count limit is greater than that

set by the limit argument.

Modification

This command was introduced.