Network Pools

When the device is serving as a DHCP server, one or more pools of IP addresses must be defined, from which the device will allocate IP addresses to clients. Each network pool contains a range of addresses that belong to a specific subnetwork. These addresses are allocated to various clients within that subnet.

When a client requests an IP address, the device as DHCP server allocates an IP address according to the following:

• Directly-attached Client—The device allocates an address from the network pool whose subnet matches the subnet configured on the device's IP interface from which the DHCP request was received.
• Remote Client—The devices takes an IP address from the network pool whose first relay subnet, which is connected directly to the client, matches the subnet configured on one of switches IP interfaces.

Up to eight network pools can be defined.

To create a pool of IP addresses, and define their lease durations:

1. Click IP Configuration > IPv4 Management and Interfaces > DHCP Server > Network Pools to display the Network Pools page.

The previously-defined network pools are displayed.

2. Click Add to define a new network pool. Note that you either enter the Subnet IP Address and the Mask, or enter the Mask, the Address Pool Start and Address Pool End.
3. Enter the fields:
Pool Name—Enter the pool name.
• Subnet IP Address—Enter the subnet in which the network pool resides.
• Mask—Enter one of following:
Network Mask—Check and enter the pool's network mask.
• Prefix Length—Check and enter the number of bits that comprise the address prefix.
• Address Pool Start—Enter the first IP address in the range of the network pool.
• Address Pool End—Enter the last IP address in the range of the network pool.
• Lease Duration—Enter the amount of time a DHCP client can use an IP address from this pool. You can configure a lease duration of up to 49,710 days or an infinite duration.
Infinite—The duration of the lease is unlimited.
• Days—The duration of the lease in number of days. The range is 0 to 49710 days.
• Hours—The number of hours in the lease. A days value must be supplied before an hours value can be added.
• Minutes—The number of minutes in the lease. A days value and an hours value must be added before a minutes value can be added.
• Default Router IP Address (Option 3)— Enter the default router for the DHCP client.
• Domain Name Server IP Address (Option 6)—Select one of the devices DNS servers (if already configured) or select Other and enter the IP address of the DNS server available to the DHCP client.
• Domain Name (Option 15)—Enter the domain name for a DHCP client.
• NetBIOS WINS Server (Option 44)— Enter the NetBIOS WINS name server available to a DHCP client.
• NetBIOS Node Type (Option 46)—Select how to resolve the NetBIOS name. Valid node types are:
Hybrid—A hybrid combination of b-node and p-node is used. When configured to use h-node, a computer always tries p-node first and uses b-node only if p-node fails. This is the default.
• Mixed—A combination of b-node and p-node communications is used to register and resolve NetBIOS names. M-node first uses b-node; then, if necessary, p-node. M-node is typically not the best choice for larger networks because its preference for b-node Broadcasts increases network traffic.
• Peer-to-Peer—Point-to-point communications with a NetBIOS name server are used to register and resolve computer names to IP addresses.
• Broadcast—IP Broadcast messages are used to register and resolve NetBIOS names to IP addresses.
• SNTP Server IP Address (Option 4)— Select one of the device's SNTP servers (if already configured) or select Other and enter the IP address of the time server for the DHCP client.
• File Server IP Address (siaddr)—Enter the IP address of the TFTP/SCP server from which the configuration file is downloaded.
• File Server Host Name (sname)—Enter the name of the TFTP/SCP server.
• Configuration File Name (file)—Enter the name of the file that is used as a configuration file.