DHCP - Global or Per Vlan?

Node ManNode Man Member Posts: 668 ■■■□□□□□□□
Hi Everybody,
Question: It appears that DHCP pools are set up on a global level. I am using a 3550 Switch. Is it possible to have 2 or more VLANs each using their own DHCP pool?


Thank you!

Comments

  • atorvenatorven Member Posts: 319
    Yes, you can create DHCP pools for multiple VLANs.
  • lrblrb Member Posts: 526
    If the switch is directly attached to clients than it will base which pool to pull the IP addresses from based on the VLAN interface the DISCOVER was received in.

    If the switch is not directly attached and a relay agent is used, the DHCP server (switch) will use the giaddr (gateway IP address) field set by the relay to determine which pool to use. Failing this, and this is really getting into the nitty gritty here, you can set the circuit-ID option (82) on the relay in combination with a ip dhcp class configuration on the server to match that circuit-ID and base the pool to use on this. We run multiple dhcpd servers at work and they don't seen to acknowledge the giaddr field which is why we set the circuit-ID for customers on the relay agents.

    Hope that helped.
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