stateful

Syntax

Hierarchy Level

Description

Configure stateful IPv6 Router Advertisement (RA) guard. In an IPv6 deployment, RA guard protects against rogue RA messages generated either maliciously or unintentionally by unauthorized or improperly configured routers connecting to the network segment. RA guard performs checks on incoming RA messages to make sure that they are sent from legitimate routers. If the sender of the RA message cannot be validated, the RA message is dropped.

Stateful RA guard enables the switch to learn about the sources of RA messages for a certain period of time. During this period, when the switch is known to be in the learning state, the information contained in attributes of received RA messages is stored and compared to the policy. When the learning period ends, the switch has a record of which interfaces are attached to links with valid IPv6 routers. If there is no valid IPv6 router attached to the interface, the switch dynamically transitions the interface from the learning state into the blocking state. Subsequent RA messages received after the transition to blocking state are dropped. If there is a valid IPv6 router attached to the interface, the interface transitions to the forwarding state, and subsequent RA messages that can be validated against the configured policy are forwarded.

You can enable stateful RA guard on an interface or on a VLAN. When you enable stateful RA guard, the initial state is Off. You initiate the learning state by issuing the request access-security router-advertisement-guard-learn command.

Default

RA guard is stateless by default.

Required Privilege Level

interface—To view this statement in the configuration.

interface-control—To add this statement to the configuration.

Release Information

Statement introduced in Junos OS Release 15.1X53-D55.