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strict-dual-isis (Protocols IS-IS)


Hierarchy Level


Configure strict dual stack (IPv4 and IPv6) support for IS-IS.

The strict-dual-isis option was introduced in Junos release 18.RR1-S6. This option avoids protocol flap when both IPv4 and IPv6 are configured on the same interface or in the same ISIS instance. The option works by introducing a holdown delay to allow both IPv4 ARP and IPv6 ND to complete before the interface is advertised. The default hold time is 15 seconds. Use the holddown argument to specify the desired delay in the range of 1 to 65535 seconds.

To configure IS-IS for strict dual stack operation include the following statements:


Strict dual stack operation for IS-IS is not enabled.



Specify the delay before ISIS advertises IPv4 and IPv6 reachability, either for the entire ISIS instance or under a specific interface. For details on interface level application, see interface (Protocols IS-IS)

By default the holdown delay is 15 seconds. Users can configure a value in the range of 1 to 65535 seconds.

Required Privilege Level

routing—To view this statement in the configuration.

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

Release Information

Statement introduced before Junos OS Release 18.4R1-S6.