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Usage guidelines
An RA message passes the check if the advertised prefixes in the message match the prefixes set by
the ACL.
If the specified ACL does not exist or does not contain a rule, the prefix match criterion does not take
effect.
Examples
# Use IPv6 basic ACL 2000 as the prefix match criterion for the RA guard policy policy1.
<Sysname> system-view
[Sysname] acl ipv6 basic 2000
[Sysname-acl-ipv6-basic-2000] rule permit source 1001:: 64
[Sysname-acl-ipv6-basic-2000] rule permit source 3124:1123:: 64
[Sysname-acl-ipv6-basic-2000] rule deny source any
[Sysname-acl-ipv6-basic-2000] quit
[Sysname] ipv6 nd raguard policy policy1
[Sysname-raguard-policy-policy1] if-match prefix acl 2000
if-match router-preference
Use if-match router-preference maximum to specify a router preference match criterion.
Use undo if-match router-preference maximum to delete the router preference match criterion.
Syntax
if-match router-preference maximum { high | low | medium }
undo if-match router-preference maximum
Default
No router preference match criterion exists.
Views
RA guard policy view
Predefined user roles
network-admin
mdc-admin
Parameters
high: Sets the maximum router preference to high. An RA message passes the check if its router
preference is not higher than high.
low: Sets the maximum router preference to low. An RA message passes the check if its router
preference is not higher than low.
medium: Sets the maximum router preference to medium. An RA message passes the check if its
router preference is not higher than medium.
Usage guidelines
A host selects a router as the default gateway according to the router preference in received RA
messages. If router preferences are the same, the host selects the default router from which the first
RA message is received.
An RA message will not pass the router preference check if the message does not have a preference
value. This RA message will be dropped.
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