4

Brand new to networking and trying different scenarios.

PC2 can successfully send packets to PC1 and the DHCP server if a static address is assigned. However, PC2 will not obtain a DHCP address from the server.

I'm assuming at this point, a helper address is required, but I'm not sure which switch or router that should be defined on

Note: All devices are on Vlan 1 - DHCP is configured correctly for 64 subnet

enter image description here

2 Answers 2

5

You configure the helper aka DHCP relay with the address of the DHCP server. The helper needs to be share a broadcast domain with the DHCP client.

In your diagram, you need to configure the helper on Router B / Gig0/0/0 and point it at 192.168.1.5. Obviously, the DHCP server needs to have a configured scope for 10.25.64.0/24.

2
  • It appears that the helper-address had to be entered AFTER the static routes were assigned. I'm not sure why, but it seemed to have worked.
    – prosportal
    Commented Feb 16, 2023 at 2:54
  • I need proper routing between the DHCP relay and the server, obviously.
    – Zac67
    Commented Feb 16, 2023 at 7:47
3

Router B. Int G0/0/0. This will forward the DHCP traffic.

3
  • Helper address will be the address of your DHCP server.
    – user87528
    Commented Feb 15, 2023 at 21:10
  • 1
    To provide a little more info. Routers are designed to block broadcast traffic. DHCP Requests are broadcast traffic. So you need to add the helper address to forward that traffic.
    – user87528
    Commented Feb 15, 2023 at 21:13
  • 1
    Routers don't "block broadcast traffic"; they don't forward broadcast traffic, because it's supposed to be link-local. The helper-address tells the router to enable it's DHCP Relay Agent, and what DHCP server to use.
    – Ricky
    Commented Feb 16, 2023 at 2:32

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.