Scope Caveat; Manual Bindings - Enterasys Security Router X-PeditionTM User Manual

When DHCP Server surveys its clients using the manual bindings of a client-identifier or hardware-
address, and host address, it generally inherits attributes from an outer down to an inner scope. But,
the DHCP Server will override outermost attributes when they are found first at the Host scope.
For instance, if a
name in the Pool scope for all clients on the 192.168.57.0 network, DHCP Server always select the
Host scope attribute.

Scope Caveat

Keep the following caveat in mind when configuring scopes: IP address pools may not be
configured to overlap. The following conditions apply:
– IP local pools may have multiple DHCP Servers per subnet for redundancy
– Each DHCP Server should have a unique address pool that does not overlap pools on
other DHCP servers
For example, a correct IP range would be configured as follows: on subnet 90.1.1.0/24, the DHCP
Server A range can be from 90.1.1.1 to 90.1.1.150, and the DHCP Server B range can be from
90.1.1.151 to 90.1.1.254

Manual Bindings

An address binding is a mapping between the IP address and MAC address or Client-ID of a
client. You can manually assign the IP address of a client or have it assigned automatically from a
pool by a DHCP Server.
Manual bindings are IP addresses that have been manually mapped to the MAC addresses of
hosts recorded in the DHCP database. An unlimited number of manual bindings are stored in
startup-config. Automatic bindings are IP addresses that have been automatically mapped to the
MAC addresses of hosts recorded in the DHCP database. Automatic bindings are saved in
persistent storage in the
Manual bindings are set up by first creating a host pool, then specifying the IP address of the client
and hardware-address or client-identifier. The hardware address is the MAC address. The client
identifier, which is required for Microsoft clients (instead of a hardware address), is formed by
concatenating the media type and the MAC address of the client.
To configure manual bindings, perform the following steps:
1. Enter ip dhcp pool <name> to create a name for the a DHCP Server address pool and acquire
DHCP pool configuration mode.
2. Enter host address [mask | prefix-length] to specify the client's IP address and subnet mask.
The prefix length sets the number of bits that comprise the address prefix. The prefix is an
alternative to specifying the network mask of the client. The prefix length must be preceded
by a forward slash (/).
3. Perform one of the following actions:
a. Specify a hardware address for the client. Enter:
hardware-address <hardware-address> <type> client-class <name>
or
b. Specify the distinct identification of the client in dotted hexadecimal notation; e.g.,
01b7.0813.8811.66, where 01 represents the Ethernet media type. Enter:
client-identifier <unique-identifier> client-class <name>
domain-name is specified for lcurtis-xp in the Host scope and another domain-
leases.cfg file.
DHCP Services
XSR User's Guide 15-5