
Dynamic Host Configuration Protocol (DHCP) Introduction
©2008 Allied Telesis Inc. All rights reserved.
Software Version 5.2.1
AlliedWare Plus
TM
Operating System Software Reference C613-50003-00 REV E
52.5
To set a subnet mask (option 1) for the address pool, use the command:
awplus(dhcp-config)#
subnet-mask <mask>
To add a domain name (option 15) for the address pool, use the command:
awplus(dhcp-config)#
domain-name <domain_name>
To add a default router (option 3) for the address pool, use the command:
awplus(dhcp-config)#
default-router <ip_address>
To add a DNS server (option 6) for the address pool, use the command:
awplus(dhcp-config)#
dns-server <ip_address>
Configuring the DHCP Relay Agent
DHCP relay agents pass BOOTP messages between servers and clients. Networks where the
DHCP or BOOTP server does not reside on the same IP subnet as its clients need the routers
attached to the subnet to act as DHCP relay agents.
Note that both BOOTP and DHCP use BOOTP messages, allowing DHCP relay agents to
relay all their packets.
Your device’s DHCP Relay Agent relays these message types:
■
BOOTREQUEST messages originating from any of the device’s interfaces to a user-defined
destination
■
BOOTREPLY messages addressed to BOOTP clients on networks directly connected to
the device
The relay agent ignores BOOTREPLY messages addressed to clients on networks not directly
connected to the device. The device treats these as ordinary IP packets for forwarding.
A BOOTREQUEST message may be relayed via unicast, multicast or broadcast methods. In the
last case, the message does not re-broadcast to the interface from which it was received. The
relay destinations are configured independently of other broadcast forwarders’ destinations
(e.g. TFTP).
The hops field in a BOOTP message records the number of hops (routers) the message has
been through. If the value of the hops field exceeds a predefined threshold, the relay agent
discards the message.
Configuring the DHCP Relay Agent
To enable the DHCP relay agent on your device, use the command:
awplus(config)#
service dhcp-relay
You must define a relay destination on one of the device’s interfaces before the relay agent can
relay packets. This is the path to the DHCP server. To define a relay destination, use the
commands:
awplus(config)#
interface <
interface-name
>
awplus(dhcp-config)#
ip dhcp-relay server-address <ip-addr>