2

If i have a DHCP Server above two routers and a cleint computer below and the client computer is connected to a router with DHCP Relay, will dhcp pass through those two routers?

Here is an example

Internet
   |
   |
 Router 0 (DHCP Server)
   |
   |
 Router 1
   |
   |
 Router 2
   |
   |
 Router with DHCP Relay pointing to Router 0
   |
   |
Client PC

Would the Client PC get DHCP relay from the Router 0? Or do i need to enable dhcp relay on all the routers?

  • 4
    I haven't seen this type of setup before, but seeing that the DHCP Relay router will send the DHCP packets as Unicast to Router 0 I'm thinking it should work. – joeqwerty Dec 1 '14 at 16:50
  • 2
    The DHCP Relay router should be sufficient. It will send the DHCP client broadcast packet as a unicast packet to Router 0. Routers 1 and 2 will forward/route this as a unicast packet. They do not need to "relay" the clients DHCP broadcast. – joeqwerty Dec 1 '14 at 17:03
  • 1
    And apologies to @joeqwerty for essentially stealing this one. If you create an answer, I'll delete mine. :) – TheCleaner Dec 1 '14 at 20:28
  • 2
    @TheCleaner: No worries. You take this one. – joeqwerty Dec 1 '14 at 20:32
  • As an aside, I mocked this up in Cisco Packet Tracer and it works fine. – joeqwerty Dec 2 '14 at 14:41
2

As long as the routing is in place such that the DHCP relay to Router 0 actually traverses Router 2 & 1 to Router 0 and back, then yes, it will work just fine. It's no different than VLANs across Layer 3 switches with IP Forwarding enabled. You could even think of it as getting a DHCP address across a WAN link from a remote DHCP server if you'd like.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

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