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DHCP relay with Multinetted VLAN

J_Warren
Frequent Visitor

DHCP relay with Multinetted VLAN

I've inherited a 10.1.0.0/16 network which only has ~400 hosts. 

What I'm trying to do is to break things down into subnets by swapping all hosts to DHCP but configuring a secondary address for static hosts to remain attached to the network.

 

Here's an example of the config:

 

vlan 3
name "Wing-1"
untagged D20
ip helper-address 10.1.1.8
ip address 192.168.3.1 255.255.255.0
ip address 10.2.100.42 255.255.0.0
tagged B24
ip igmp
exit

 

The problem is I want any DHCP requests coming from there to be sent at 192.168.3.0/14 requests, but they default to the 10.2 network.

 

Is there a way to specify the DHCP range I want to relay into? 

Something along the lines of ip address 192.168.3.1 255.255.255.0 primary?

2 REPLIES
paulgear
Esteemed Contributor

Re: DHCP relay with Multinetted VLAN

What is your "dhcp-relay option 82" setting?  I haven't done this with multiple gateway addresses on the switch before, but it should work the same.

 

The trick is that the DHCP server selects the address based on the ip address of the relay agent, so as long as the option 82 is set right, it should use the IP address on which it received the request.

Regards,
Paul
J_Warren
Frequent Visitor

Re: DHCP relay with Multinetted VLAN

Sorry I never responded, been busy and haven't checked the forums

The solution I found was to do

 

ip bootp-gateway 192.168.3.0

 

Much easier than messing with option 82.