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Cisco ASA 5500 Series Configuration Guide using ASDM
Chapter31 Configuring IPv6 Neighbor Discovery
Suppressing Router Advertisement Messages
Suppressing Router Advertisement Messages
Router advertisement messages are automatically sent in response to router solicitation messages. You
may want to disable these messages on any interface for which you do not want the ASA to supply the
IPv6 prefix (for example, the outside interface).
To suppress the router lifetime value in IPv6 router advertisements on an interface, perform the following
steps:
Step1 Choose Configuration > Device Setup > Interfaces.
Step2 Select the interface for which you want to suppress the router advertisement transmissions. The interface
must have been configured with an IPv6 address.
Step3 Click Edit.
The Edit Interface dialog box appears with three tabs: General, Advanced, and IPv6.
Step4 Click the IPv6 tab.
Step5 Check the Suppress RA check box.
Step6 Verify that the router advertisement message is suppressed on the interface that is configured for the IPv6
address.
Configuring the IPv6 Prefix
To configure the which IPv6 prefixes are included in IPv6 router advertisements, perform the following
steps:
Step1 In the Interface IPv6 Prefixes area, click Add.
The Add IPv6 Prefix for Interface dialog box appears.
Step2 Enter the IPv6 address with the prefix length.
Step3 (Optional) To configure the IPv6 address manually, check the No Auto-Configuration check box. This
setting indicates to hosts on the local link that the specified prefix cannot be used for IPv6
autoconfiguration.
Step4 (Optional) To indicate that the IPv6 prefix is not advertised, check the No Advertisements check box.
Step5 (Optional) The Off Link check box indicates that the specified prefix is assigned to the link. Nodes
sending traffic to addresses that contain the specified prefix consider the destination to be locally
reachable on the link. This prefix should not be used for on-link determination.
Step6 In the Prefix Lifetime area, click the Lifetime Duration radio button, and specify the following:
a. A valid lifetime for the prefix in seconds from the drop-down list. This setting is the amount of time
that the specified IPv6 prefix is advertised as being valid. The maximum value represents infinity.
Valid values are from 0 to 4294967295. The default is 2592000 (30 days).
b. A preferred lifetime for the prefix from the drop-down list. This setting is the amount of time that
the specified IPv6 prefix is advertised as being preferred. The maximum value represents infinity.
Valid values are from 0 to 4294967295. The default setting is 604800 (seven days).