valid-lifetime (DHCPv6)

Specifies how long the IPv6 prefix remains valid for onlink determination.
Syntax
valid-lifetime interval
Command Default

The valid lifetime interval is 0 seconds by default.

Parameters
interval
Specifies the time interval in seconds. The default is 0 seconds.
Modes

DHCPv6 server configuration mode

DHCPv6 subnet configuration mode

Usage Guidelines

The valid lifetime option should only be specified after the preferred life-time is configured. The valid lifetime interval must be greater than or equal to the preferred lifetime interval. Refer to the preferred-lifetime (DHCPv6) command for more information.

When configuring the DHCPv6 server using this command along with the preferred-lifetime (DHCPv6), renewal-time (DHCPv6), and rebind-time (DHCPv6) commands, enter the commands in the following order:

  1. preferred-lifetime (DHCPv6)
  2. valid-lifetime (DHCPv6)
  3. rebind-time (DHCPv6)
  4. renewal-time (DHCPv6)
Note: Failure to enter the commands in this order when configuring the DHCPv6 server results in a CLI error.

If a valid lifetime is not configured in DHCPv6 subnet configuration mode, the globally configured valid lifetime is inherited.

The DHCPv6 lease expiry is calculated based on the current-time with the valid-lifetime configured, and must not exceed the value of 2147483647 seconds. The below error occurs when the valid-lifetime configuration exceeds the allowed value:

device(config-dhcp6-subnet)# valid-lifetime 4294967291
Error: valid-lifetime + current-time must not exceed 2147483647
device(config-dhcp6-subnet)#

The no form of the command restores the default. If the no form of the command is used with an unconfigured value, an error message appears.

Examples

The following example sets the valid lifetime to 100 seconds.

device# configure terminal
device(config)# ipv6 dhcp6-server enable
device(config-dhcp6)# valid-lifetime 100

The following example sets the valid lifetime to 200 seconds in DHCPv6 subnet configuration mode.

device# configure terminal
device(config)# ipv6 dhcp6-server enable
device(config-dhcp6)# subnet6 3ffe:501:ffff:100::/64
device(config-dhcpv6-subnet)# valid-lifetime 200
History
Release version Command history
08.0.90 This command was introduced.