User Manual

Enterasys X-Pedition User Reference Manual 129
Chapter 10
DHCP
Configuration Guide
DHCP Overview
The Dynamic Host Configuration Protocol (DHCP) server on the XP provides dynamic address
assignment and configuration to DHCP capable end-user systems, such as Windows 95/98/NT and
Apple Macintosh systems. You can configure the server to provide a dynamic IP address from a
pre-allocated pool of IP addresses or a static IP address. You can also configure parameters for use
by the clients, such as default gateway and network masks, and system-specific parameters, such as
NetBIOS Name Server and NetBIOS node type of the client.
The amount of time that a particular IP address is valid for a system is called a lease. The XP
maintains a lease database which contains information about each assigned IP address, the MAC
address to which it is assigned, the lease expiration, and whether the address assignment is dynamic
or static. The DHCP lease database is stored in flash memory and can be backed up on a remote
TFTP or RCP server. You can configure the intervals at which updates to the lease database (and
backup) are done. Upon system reboot, the lease database will be loaded either from flash memory
or from the TFTP or RCP server.
Note: Because the Command Line Interface does not validate the RCP and TFTP remote host
addresses and passwords during DHCP configuration, you must ensure that you specify
them correctly.
Note: The XP DHCP server is not designed to work as the primary DHCP server in an enterprise
environment with hundreds or thousands of clients that are constantly seeking IP address
assignment or reassignment. A standalone DHCP server with a redundant backup server
may be more suitable for this enterprise environment.