DHCP Server on a different subnet

Hello,

How do I allow my 2PCs on 172.16.0.0 subnet recognise that my DHCP Server on 192.168.1.0 subnet is there and is wanting to share a range of IPs? Thanks for your help in advance as always!

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4_lom

You need to add a DHCP relay on your router.

See here for more details:

DHCP - Configuring the Cisco IOS DHCP Relay Agent [Support] - Cisco Systems

Ltat42a

Here's an example done in Packet Tracer -
https://www.youtube.com/watch?v=56Q-w0cY6NI

satishtech

R3(config)#interface of 172.16.0.0/16 subnet
R3(config-if)#ip helper-address dhcp-server-ip

redgunner

Thanks for this - Got it working.

Does IP Helper Address listen for particular ports or is it all ports? For example, could I block DNS or maybe a webserver port?

satishtech

DHCP Ports

67 UDP DHCP-SERVER bootps
68 UDP DHCP-CLIENT bootpc

extended ACL blocking port 67 may work.

redgunner

Without focusing on ACL Lists / Firewalls etc...

What ports does ip helper address listen for?