Dell PowerEdge M420 Reference Manual page 976

Parameter
valid-lifetime
infinite
preferred-lifetime
no-autoconfig
off-link
Default Configuration
604800 seconds is the default value for valid-lifetime, 2592000 seconds for
preferred lifetime.
Command Mode
Interface Configuration (VLAN, Tunnel, Loopback) mode
User Guidelines
The router advertises its global IPv6 prefixes in its router advertisements
(RAs). An RA only includes the prefixes of the IPv6 addresses configured on
the interface where the RA is transmitted. Addresses are configured using the
ipv6 address interface configuration command. Each prefix advertisement
includes information about the prefix, such as its lifetime values and whether
hosts should use the prefix for on-link determination or address auto-
configuration. Use the ipv6 nd prefix command to configure these values.
The ipv6 nd prefix command will allow you to preconfigure RA prefix values
before you configure the associated interface address. In order for the prefix
to be included in RAs, you must configure an address that matches the prefix
using the ipv6 address command. Prefixes specified using ipv6 nd prefix
without an associated interface address will not be included in RAs and will
not be committed to the device configuration.
Example
The following example sets the IPv6 prefixes to include in the router
advertisement.
976
IPv6 Routing Commands
Description
Valid lifetime of the router in seconds. (Range: 0–4294967295
seconds.)
Indicates lifetime value is infinite.
Preferred-lifetime of the router in seconds. (Range:
0–4294967295 seconds.)
Do not use Prefix for autoconfiguration.
Do not use Prefix for onlink determination.