# IPv6 Prefix List Configuration

A prefix list is a table containing IPv6 prefixes. When there are entries in the list, the router includes them in the RAs it sends to on-link hosts. Each time a host receives such a RA, it can use the prefixes to perform address autoconfiguration.

New IPV6 Prefix/Length: Specifies a prefix that the receiving hosts on the same link can use to autoconfigure themselves. The prefix consists of a valid IPv6 address and prefix length, as with 3ffe::200:1234:7/64. Note: The NetScreen device advertises global prefixes, never link-local prefixes.

Valid Lifetime: Specifies the interval of time (in days, hours, minutes, and seconds) that hosts may consider the prefix entry valid after receiving the last transmitted RA.

Preferred Lifetime: Specifies how much of the Valid Lifetime interval the address is preferred over the others. After the Preferred Lifetime elapses, the NetScreen device checks for other prefixes with Preferred Lifetime settings. If there are no others, the device uses the current Valid Lifetime.

Prefix Flags:

Autonomous: Instructs the host receiving the router advertisement to use stateless configuration to generate addresses from the specified prefix.

Onlink: Instructs the host receiving the router advertisement that the specified prefix is onlink and should use the prefix for stateless configuration.

To Add a Prefix To the Prefix List

1. On the Prefix List page, enter the necessary information for an IPv6 prefix.

2. Click Add.