Foundry Networks Switch and Router, Installation And Configuration Manual

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Foundry Switch and Router Installation and Configuration Guide
15 - 82 December 2000
Figure 15.12 DHCP offers are forwarded back toward the requestors
Configuring DHCP Assist
You can associate a gateway list with a port. You must configure a gateway list when DHCP Assist is enabled on
a Foundry Layer 2 Switch. The gateway list contains a gateway address for each sub-net that will be requesting
addresses from a DHCP server. The list allows the stamping process to occur. Each gateway address defined on
the Layer 2 Switch corresponds to an IP address of the Foundry router interface or other router involved.
Up to eight addresses can be defined for each gateway list in support of ports that are multi-homed. When
multiple IP addresses are configured for a gateway list, the Layer 2 Switch inserts the addresses into the
discovery packet in a round robin fashion.
Up to 32 gateway lists can be defined for each Layer 2 Switch.
USING THE CLI
EXAMPLE:
To create the configuration indicated in Figure 15.11 and Figure 15.12:
FastIron(config)# dhcp-gateway-list 1 192.95.5.1
FastIron(config)# dhcp-gateway-list 2 200.95.6.1
FastIron(config)# dhcp-gateway-list 3 202.95.1.1 202.95.5.1
FastIron(config)# int e 2
FastIron(config-if-2)# dhcp-gateway-list 1
FastIron(config-if-2)# int e8
FastIron(config-if-8)# dhcp-gateway-list 3
Server
Server
DHCP
Server
207.95.7.6
Link
Activity
Link
Activity
Power
Console
FastIron Workgroup
192.95.5.x
Host 1
192.95.5.10 200.95.6.15
200.95.6.x
Host 2
Sub-net 1
Host 3 Host 4
Router
202.95.1.x
Sub-net 3
Sub-net 2
202.95.5.25
202.95.1.35
DHCP response with IP addresses
for Sub-nets 1, 2, 3 and 4
192.95.5.10
200.95.6.15
202.95.1.35
202.95.5.25
202.95.5.x
Sub-net 4
Step 4:
DHCP Server extracts the gateway
address from each packet and
assigns IP addresses for each
host within the appropriate
range.
Step 5:
IP addresses are distributed
to the appropriate hosts.