Specifying a primary subnet and multiple secondary subnets in a DHCP address pool

About a primary subnet and multiple secondary subnets in a DHCP address pool

If an address pool has a primary subnet and multiple secondary subnets, the server assigns IP addresses on a secondary subnet when the primary subnet has no assignable IP addresses.

Restrictions and guidelines

IP addresses specified by the forbidden-ip command are not assignable in the current address pool, but are assignable in other address pools. IP addresses specified by the dhcp server forbidden-ip command are not assignable in any address pool.

Specifying a primary subnet and multiple secondary subnets

  1. Enter system view.

    system-view

  2. Enter DHCP address pool view.

    dhcp server ip-pool pool-name

  3. Specify the primary subnet.

    network network-address [ mask-length | mask mask ]

    By default, no primary subnet is specified.

    You can specify only one primary subnet in each address pool. If you execute the network command multiple times, the most recent configuration takes effect.

  4. (Optional.) Specify a secondary subnet.

    network network-address [ mask-length | mask mask ] secondary

    By default, no secondary subnet is specified.

    You can specify a maximum of 32 secondary subnets in one address pool.

  5. (Optional.) Return to address pool view.

    quit

Setting the lease duration for dynamically allocation IP addresses

  1. Enter system view.

    system-view

  2. Enter DHCP address pool view.

    dhcp server ip-pool pool-name

  3. Set the address lease duration.

    expired { day day [ hour hour [ minute minute [ second second ] ] ] | unlimited }

    The default setting is 1 day.

Excluding IP addresses from dynamic allocation

  1. Enter system view.

    system-view

  2. Enter DHCP address pool view.

    dhcp server ip-pool pool-name

  3. Exclude the specified IP addresses from dynamic allocation.

    forbidden-ip ip-address&<1-8>

    By default, all IP addresses in the DHCP address pool are assignable.

    To exclude multiple address ranges from the address pool, repeat this step.

  4. (Optional.) Exclude the specified IP addresses from dynamic allocation in system view.

    1. Return to system view.

      quit

    2. Exclude the specified IP addresses from dynamic allocation globally.

      dhcp server forbidden-ip start-ip-address [ end-ip-address ] [ vpn-instance vpn-instance-name ]

      By default, except for the IP address of the DHCP server interface, IP addresses in all address pools are assignable.

      To exclude multiple address ranges globally, repeat this step.