Configuring Address Pools
You must configure IP address pools for each IP interface that will provide
addresses to attached clients via the DHCP server.
Command Usage
• First configure address pools for the netw ork interfa ces. Then you can manua lly
bind an address to a specific client if required. H owever, n ote that any stat ic host
address must fall within the range of an existing network a ddress po ol. You can
configure up to 8 network address pools, an d up to 32 manually bound host
address pools (i.e., one address per host pool ).
• When a client request is received, the switch first ch ecks f or a network ad dress
pool matching the gateway where the request originated (i.e., if the requ est was
forwarded by a relay server). If there is no gat eway in the cli ent request (i .e., the
request was not forwarded by a rela y serv er), the swit ch search es for a netwo rk
pool matching the interface through which the client request was receive d. It then
searches for a manually configured host address that falls within the matching
network pool. If no manually configured host address is found, it ass igns an
address from the matching network address pool. However, if no matching address
pool is found the request is ignored.
• When searching for a manual binding, the switch compares the client identifier and
then the hardware address for DHCP clients. Since BOOTP clients cannot transmit
a client identifier, you must configure a hardw are addr ess for t his host type. If no
manual binding has been specified for a host entr y with a hard ware add ress or
client identifier, the switch will assign an address from the fi rst ma tching net work
pool.
• If the subnet mask is not specified for network or hos t add re ss pools , th e cla ss A,
B, or C natural mask is used (see page 20-5). The DHCP server assu mes that all
host addresses are available. You can exclude subsets of th e address spac e by
using the IP Excluded Address field on the DHCP Server General configuration
page.
Command Attributes
Creating a New Address Pool
• Pool Name – A string or integer. (Range: 1-8 charact ers)
• Type – Shows is address pool type is Network or Host.
• IP Address – The IP address upon which th e pool is based.
• Mask – Shows the network (or subnet) and th e host portio n of the addre ss pool.
• Active Po ol – The ad dresses provided by thi s pool, including those speci fied by
the IP address and network mask, but minus those excluded on the DHCP server’s
General Configuration page.

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CLI
– This example enables the DHCP and sets an excluded address range.
Console(config)#service dhcp
Console(config)#ip dhcp excluded-address 10.1.0.250 10.1.0.254
Console#
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9
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Dynamic Host Configuration Protocol

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