Create a Superscope

While I never recommend the use of Superscopes as they are usually relevant to a bad network design. I know that sometimes networks are inherited and not the fault of the person having to perform this action;thus, I am going to provide a lean set of steps to configure this assuming you know your way around Microsoft DHCP server and have a few requirements met:

I am going to presume you have multiple subnets inside VLAN 1 and the config on a Cisco would look like this:

vlan 1
int vlan1
ip address
ip address secondary
ip address secondary

This is stereotypical of multiple subnets inside a single VLAN and that is typically VLAN 1.

Next, you need to configure the superscope itself. This is simple enough to do with the wizard inside Microsoft DHCP and shouldn’t need explaining here.

After this is done you NEED to either:

  1. Assign an IP address to a unique interface that is inside each DHCP scope
  2. Assign an IP address as a “sub interface” to your main Ethernet adapter with an IP in each DHCP scope

This is a requirement because if you don’t have an IP address assigned to that interface you’re either not going to get a proper IP address or it may have some odd behavior.

Once again, I never recommend this solution as it requires you configure multiple subnets inside a single VLAN and that goes against all “standard practices” of 1 IP subnet per VLAN.

Do you require IP HELPER with a superscope? Yes and no, it depends. Are all the subnets inside a single VLAN with “secondary” addresses? If yes, you don’t need one. If you other VLANS that are Layer 3 aware and for some odd reason still wanted to use a superscope, or are forced to thanks to multinetting, then yes, you will need an IP HELPER. The bottom line is that Superscopes are a TRANSITION tool and not a solution. Break up your subnets into difference VLANs and in each VLAN place an IP HELPER in each VLAN. Then, at the DHCP server setup multiple independent scopes and let the standards do the rest.