vlans and dhcp superscopes

[Danny Mainprize]

Is there a way to allow 1 vlan to get addresses from a superscope with multiple scopes in it?

Vlan 101 - default gateway is 10.0.101.1

I want to have a DHCP superscope with 10.0.101.2-250 and 10.0.105.2 - 250.  I can create the superscope no problem, I am just not sure what to point my ip dhcp relay command at on the switch.  The switch is a 3650X and the dhcp server is a MS Server 2012R2. 

Basically I need to combine two discontinuous dhcp pools with a single gateway address.  Normally I would just kill all the old DHCP scopes and build it right, but my problem does not allow me that luxury.

[lpassmore]

Hi Danny

You haven't really said what the IP address associated with VLAN 101 is, but to do what you want you will need to configure it something like this:

int vlan101
  ip address 10.0.101.1 255.255.255.0
  ip address 10.0.105.1 255.255.255.0 secondary
  ip helper (your DHCP server address)

ip dhcp smart-relay

This will try first to send the request to the server using the main IP address and then if it doesn't see a DHCP offer come back it will try again using the secondary address