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DHCP Address-Assignment Pools

 

Address pool is a set of Internet Protocol addresses available for allocation to users, such as in host configurations with the DHCP. An address-assignment pool can support either IPv4 address or IPv6 addresses. You cannot use the same pool for both types of address. For more information, read this topic.

Configuring Address-Assignment Pools

The address-assignment pool feature for SRX300, SRX320, SRX340, SRX345, SRX550M, and SRX1500 devices enables you to create address pools that can be shared by different client applications such as DHCPv4 or DHCPv6.

To configure an address-assignment pool:

  1. Configure the address-assignment pool name and specify the addresses for the pool.

    See Configuring an Address-Assignment Pool Name and Addresses.

  2. (Optional) Configure named ranges (subsets) of addresses.

    See Configuring a Named Address Range for Dynamic Address Assignment.

  3. (Optional;IPv4 only) Create static address bindings.

    See Configuring Static Address Assignments.

  4. (Optional) Configure attributes for DHCP clients.

    See Configuring DHCP Client-Specific Attributes for Address-Assignment Pools.

Configuring an Address-Assignment Pool Name and Addresses

When configuring an address-assignment pool on SRX300, SRX320, SRX340, SRX345, SRX1500, and SRX550M devices, you must specify the name of the pool and its addresses.

To configure an IPv4 address-assignment pool:

  1. Configure the name of the pool and specify the IPv4 family.
  2. Configure the network address and the prefix length of the addresses in the pool.
Note

You can configure an IPv4 address-assignment pool in a routing instance by configuring the address-assignment statements at the[edit routing-instance routing-instance-name] hierarchy level. For example [edit routing-instances routing-instances name access address-assignment pool blr-pool family inet]. The above steps shows only the [edit access] configuration.

Configuring a Named Address Range for Dynamic Address Assignment

You can optionally configure multiple named ranges, or subsets, of addresses within an address-assignment pool. During a dynamic address assignment, a client can be assigned an address from a specific named range. To create a named range, you specify a name for the range and define the address range.

Note

Supported only on SRX300, SRX320, SRX340, SRX345, SRX1500, and SRX550M devices.

To create a named range within an IPv4 address-assignment pool:

  1. Specify the name of the address-assignment pool.
  2. Configure the name of the range and the lower and upper boundaries of the addresses in the range.
Note

To configure named address ranges in a routing instance, configure the address-assignment statements in the [edit routing-instances] hierarchy level.

Configuring Static Address Assignments

You can optionally create a static IPv4 address binding by reserving a specific address for a particular client. The address is removed from the address-assignment pool so that it is not assigned to another client. When you reserve an address, you identify the client host and create a binding between the client MAC address and the assigned IP address.

Note

This feature is supported on SRX300, SRX320, SRX340, SRX345, SRX550M, and SRX1500 devices.

To configure a static IPv4 address binding:

  1. Specify the name of the IPv4 address-assignment pool containing the IP address you want to reserve for the client.
  2. Specify the name of the client for the static binding, the client MAC address, and the IP address to reserve for the client. This configuration specifies that the client with MAC address 01:03:05:07:09:0b is always assigned IP address 192.168.10.2.
Note

To configure static binding for an IPv4 address in a routing instance, configure the address-assignment statements in the [edit routing-instances] hierarchy.

Configuring Address-Assignment Pool Linking

Address-assignment pool linking enables you to specify a secondary address pool for the device to use when the primary address-assignment pool is fully allocated. When the primary pool has no available addresses remaining, the device automatically switches over to the linked secondary pool and begins allocating addresses from that pool. The device uses a secondary pool only when the primary address-assignment pool is fully allocated.

You can create a chain of multiple linked pools. For example, you can link pool A to pool B, and link pool B to pool C. When pool A has no available addresses, the device switches to pool B for addresses. When pool B is exhausted, the device switches to pool C. There is no limit to the number of linked pools in a chain. However, you cannot create multiple links to or from the same pool—a pool can be linked to only one secondary pool, and a secondary pool can be linked from only one primary pool.

To link a primary address-assignment pool named pool1 to a secondary pool named pool2 on SRX1500, SRX5400, SRX5600, or SRX5800 devices: