What Is A DHCP Scope?

A DHCP is a network protocol used on IP networks, where the DHCP servers automatically offer and assign IP addresses and other network parameters to a DHCP-enabled client. It helps to eliminate the need for you to perform time-consuming tasks of setting up and managing a TCP/IP network. Apart from that, DHCP is also effective for creating a tailored configuration for certain types of clients.

As you now know, DHCP servers will automatically offer and assign IP addresses upon a client’s request. However, you need to understand that this doesn’t just happen. Before IP addresses can get assigned to clients, the DHCP servers must first be configured with a scope. That said, here’s a burning question; what exactly is a DHCP scope?

A DHCP scope is a range of IP addresses that are available for the DHCP servers to lease out to DHCP-enabled clients on a given subnet. Its primary function is to decide which IP addresses the servers get to offer the clients. Interestingly, users can create as many scopes as required on a DHCP server.

Apart from IP addresses, it’s worth knowing that you can also use DHCP scopes to assign optional network parameters to clients. In the rest of this article, you’ll find out everything you need to know about DHCP scopes, including how you can successfully create them.

What Is a DHCP Scope and Why Is It Important For You?

As previously stated, a DHCP scope is a valid range of IP addresses or other optional parameters available for the DHCP servers to lease out to clients upon their requests. Furthermore, without configuring the server with a scope, it becomes pretty much impossible for the servers to offer or assign DHCP-enabled clients IP addresses.

Things to consider before creating DHCP scopes

Before going ahead to create a valid DHCP scope, there are a few factors that you must consider. 

• First, you need to check whether or not there are multiple DHCP servers on the network. If yes, you must create at least one DHCP scope for each of the servers.

• Also, check and see whether there is a workstation on the network that needs a static IP address. In case you have any, you must exclude it from the scope. The purpose of that is to help you eliminate the chance of generating a duplicate IP address.

• Furthermore, you need to understand that you can always configure a single server with multiple DHCP Scopes.

• Also, you need to keep in mind that you can’t share Scope information between different DHCP servers.

• That’s not all; you must also ensure that the IP addresses in each Scope don’t overlap. Of course, the purpose of that is to eliminate every chance of generating duplicate IP.

Properties of DHCP Scope

Here are the different properties of a valid DHCP scope:

• The network ID for the range of IP addresses

• The subnet mask for the network ID

• The available range of Network IP address for DHCP-enabled clients

• Router – This is what enables the client to gain access to remote networks.

• Exclusion range – a term used for the range of IP addresses in the scope that is often excluded from being leased.

• The lease duration – the period, in which the DHCP server holds and manages the leased IP address on behalf of the client.

• Scope name – this is an alphanumeric identifier. It’s only handy for administrative purposes.

What Are the Different DHCP Scope Types?

Depending on a couple of factors, DHCP Scope is divided into different types; normal scope, multicast scope, and superscope. You can check below to find out the meaning of each of them.

1. Normal scope: How to successfully create one

Creating a normal DHCP scope is a pretty straightforward process that you can achieve through the DHCP management console. All you need to do is to open the console and select the New Scope option. You can follow the steps below to create a normal DHCP scope successfully:

• Open the management console, right-click the DHCP server and select the “New Scope” option.
• After that, the new scope wizard will open, prompting you to enter the required parameters.
• First, start by entering a name and description for the new scope, after that click next.
• Up next, you need to enter the range of IP addresses that will be available to clients on a particular subnet.
• Now, enter the exclusion range – that’s the range of IP addresses that you exclude from being leased.
• Up next, proceed by specifying the least duration. How long do you want the DHCP server to hold and manage the IP address for you? Usually, the default duration is 8 days.
• Now, would you like to configure additional DHCP options? If yes, you can use the  Configure DHCP Options screen by clicking “yes” to do just that. If not, all you need to do is to click “no” on the screen and then proceed  to click “finish.”

Activating the scope

It’s worth knowing that IP addresses you created won’t be leased to clients immediately after setting up the new scope. For them to become leasable, you must activate the new scope.

First, note that the new scope will appear within the DHCP management console. To locate it, you’ll notice a red arrow beside it. After finding the new scope, all you need to do is to right-click it and select the “Activate option.” Doing that, you’ll notice the disappearance of the red arrow, meaning the IP addresses from the scope are now ready to be leased to clients.

2. Superscopes

Another type of DHCP scope that you can choose to create is the superscopes. The benefit of this type of DHCP scope is that they enable a DHCP server to assign leases to clients on multiple subnets. Furthermore, superscopes make it easy for administration in terms of a multi-netted environment. 

3.  Multicast Scopes

The multicast scopes are different from the regular scopes and superscopes. They are usually supported through a protocol, called the Multicast Address Dynamic Client Allocation Protocol (MADCAP).