10 DHCP Best Practices

DHCP, or Dynamic Host Configuration Protocol, is a network protocol used to automatically assign IP addresses to devices on a network. DHCP is a vital component of any network, as it helps to ensure that all devices on the network have a valid IP address.

While DHCP is a simple protocol, there are a few best practices that should be followed in order to ensure that it is properly configured and working as intended. In this article, we will discuss 10 DHCP best practices that you should follow in order to ensure that your network is running smoothly.

1. Use a DHCP server

When you use a DHCP server, your devices can automatically receive their IP address and other network configuration settings from the server. This means that you don’t have to manually configure each device on your network, which can save you a lot of time and effort.

Additionally, using a DHCP server can help to ensure that all of your devices are properly configured and that they have the correct IP address. This can help to prevent networking problems and can make it easier to troubleshoot any issues that do arise.

Finally, DHCP servers can provide a number of other benefits, such as the ability to remotely manage your network, the ability to track usage statistics, and more.

2. Configure the DHCP scope properly

The DHCP scope is the range of IP addresses that the DHCP server can hand out to clients. If the DHCP scope is not configured properly, then the DHCP server may hand out IP addresses that are already in use, which can cause all sorts of problems on the network.

To avoid this, make sure that the DHCP scope is properly configured before you deploy the DHCP server. You can use the Add-DhcpServerv4Scope cmdlet to add a new DHCP scope, and the Set-DhcpServerv4Scope cmdlet to modify an existing DHCP scope.

3. Create an exclusion range

By default, the DHCP server will hand out addresses from the entire scope. However, you can configure the DHCP server to exclude a range of IP addresses from being handed out.

The exclusion range is important because it allows you to reserve IP addresses for static devices. For example, you might want to exclude the range 192.168.1.100-192.168.1.200 and use those IP addresses for servers, printers, and other devices that need a static IP address.

Creating an exclusion range is a simple process and only takes a few minutes. In most cases, you’ll want to create an exclusion range that’s at least twice the size of your largest subnet.

4. Use multiple scopes

When you have multiple scopes, you can more easily control which devices get which IP addresses. This is important because it allows you to segment your network into different subnets, each with its own range of IP addresses.

For example, you might have a scope for your office computers, another for your wireless devices, and another for your printers. By using multiple scopes, you can make sure that each device gets the right IP address and that they’re all on the correct subnet.

Not only does this make your network more organized and easier to manage, but it also makes it more secure. By segmenting your network into different subnets, you can better control access and prevent unauthorized devices from getting onto your network.

5. Reserve addresses for servers and printers

If you don’t reserve addresses for servers and printers, they will likely be assigned a different address each time they reboot or renew their lease. This can cause problems because other devices on the network may have been configured to use the server or printer’s old address.

By reserving an address for a server or printer, you can avoid these potential problems.

6. Set lease duration to 8 days or less

If a DHCP server goes down, or a client’s IP address changes for any reason, the client will need to request a new IP address from the DHCP server. If the lease duration is set too high, it could take a long time for the client to get a new IP address, and in the meantime, they will be unable to connect to the network.

By setting the lease duration to 8 days or less, you can be sure that clients will always be able to get a new IP address quickly, without having to wait for the DHCP server to come back online.

7. Enable DNS dynamic updates

When a DHCP client obtains a new IP address, it will register the new address with DNS. This ensures that the DNS record for the host is always up-to-date, which is important for both name resolution and security.

If dynamic updates are not enabled, the DHCP server will need to be manually configured to update DNS records. This is error-prone and can lead to out-of-date DNS records.

Enabling dynamic updates is a simple task that can save you a lot of headaches down the road.

8. Disable NetBIOS over TCP/IP

NetBIOS is a legacy protocol that’s no longer needed for most modern networks. It was designed for small, local networks and it doesn’t scale well. Additionally, NetBIOS traffic can be used in attacks, so it’s best to disable it if you don’t need it.

To disable NetBIOS over TCP/IP, open the Network and Sharing Center and click on Change adapter settings. Right-click on your network adapter and select Properties. Click on the Internet Protocol Version 4 (TCP/IPv4) entry and click Properties. Select the Advanced button and uncheck the box next to Enable NetBIOS over TCP/IP. Click OK to save your changes.

9. Don’t use WINS with DHCP

When WINS is used with DHCP, it can cause a number of problems. One problem is that the WINS server will constantly be changing, which can lead to inconsistency and errors. Additionally, using WINS with DHCP can also lead to security issues, as it can allow unauthorized users to access the network.

Therefore, it’s important to make sure that WINS is not being used with DHCP. If you’re not sure how to do this, you can contact your DHCP server administrator or consult your DHCP server documentation.

10. Split your network into VLANs

When you have a single network, all of your devices are on the same broadcast domain. This means that every device will receive every broadcast packet sent out by any other device on the network.

This can be very inefficient, especially if you have a lot of devices on your network. By splitting your network into VLANs, you can reduce the number of broadcasts that each device has to process.

Additionally, VLANs can help improve security by isolating different types of devices from each other. For example, you could put all of your servers on one VLAN and all of your workstations on another.

Finally, VLANs can also make it easier to manage your network because you can configure different policies for different types of devices.