Example config DHCP over subinterface

Unanswered Question
Apr 3rd, 2007

Dear All,

I need some help. In my network we separate network / department.

Example

vlan 1 Finance

vlan 2 Technical

vlan 3 Sell

Now We would like to implement DHCP as Centralize Server.

DHCP Server has only 1 interface locate in vlan 1

How can we config in router 3660 to let other vlan receive "Assign IP" from DHCP server in Vlan1

Here is Example configuration in router

interface FastEthernet1/0.1

encapsulation dot1Q 1 native

ip address 10.15.12.254 255.255.255.0

no ip redirects

no ip proxy-arp

ip directed-broadcast

no cdp enable

!

interface FastEthernet1/0.2

encapsulation dot1Q 2

ip address 192.168.90.1 255.255.255.0

no ip redirects

no ip proxy-arp

ip directed-broadcast

!

interface FastEthernet1/0.3

encapsulation dot1Q 3

ip address 172.17.0.254 255.255.255.0

ip directed-broadcast

no ip redirects

no ip proxy-arp

no cdp enable

!

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Overall Rating: 4.2 (4 ratings)
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ankbhasi Tue, 04/03/2007 - 05:14

Hi Sirapat,

Under Interface fa1/0.2 and interface fa1/0.3 add one command "ip helper-address "

This will redirect your DHCP traffic from other vlans as unicast to vlan 1.

HTH

Ankur

*Pls rate all helpfull post

Richard Burts Tue, 04/03/2007 - 18:14

Sirapat

I believe that Ankur has given the correct command to get each of the subinterfaces to forward DHCP requests to the DHCP server. I would add that you need to verify that the DHCP server has a separate scope configured for each of the subnets on each of the subinterfaces.

HTH

Rick

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