DHCPv6 lease times on a Cisco IOS device

When configuring a DHCPv6 server on a Cisco IOS device, you can specify the lease time using the following command under the IPv6 DHCP configuration mode:

R1(config)#ipv6 dhcp pool my_pool
R1(config-dhcpv6)#information refresh ?
  <0-365>   Days
  infinite  Infinite lease

The lease time interval is represented by a 32 bit value, and is measured in seconds. On a Cisco device, it is configured in days, as seen above.

A lease time value of all ones in the 32-bit value indicates an infinite lease time. This corresponds to a decimal value of 4294967295.

By default, the lease time for a DHCPv6 server on a Cisco IOS device is 30 days.

To view the configured lease time, issue the following command

R1(config)#exit
R1#show ipv6 dhcp pool
DHCPv6 pool: my_pool
  Information refresh: 4294967295
  Active clients: 0
R1#

Notice the above information shows a value of 4294967295 seconds which indicates an infinite lease time.

Links:

https://datatracker.ietf.org/doc/html/rfc8415#page-127

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_dhcp/configuration/15-mt/dhcp-15-mt-book/ip6-dhcp-nis-sntp.html#GUID-404D053B-E8D3-4724-B687-A67C1A183672

https://forum.networklessons.com/t/cisco-dhcpv6-server-configuration/1116/68?u=lagapides