Understanding DHCP And DHCP Snooping: How To Secure Your Network

In the world of network security, Dynamic Host Configuration Protocol (DHCP) and DHCP snooping are two important concepts that many IT professionals have to understand. In this blog post, we’ll look at what each one is, how they work together, and how they can be used to secure your network from potential attacks. We’ll also cover some best practices for implementing both protocols as a part of your overall security strategy. By the end of this article, you will have a better understanding of how DHCP and DHCP snooping can help protect your business from malicious actors and keep your network safe.

DHCP and DHCP Snooping Basics

DHCP (Dynamic Host Configuration Protocol) is a network protocol used to automatically assign IP addresses and other network settings to devices on a network. DHCP snooping is a security feature that can be configured on switches to help prevent malicious devices from impersonating DHCP servers and handing out illegitimate IP addresses.

hen DHCP snooping is enabled on a switch, the switch will inspect all DHCP traffic passing through it and keep track of which IP addresses have been assigned to which MAC addresses. The switch will then only allow traffic from legitimate DHCP servers and will block any traffic from devices with IP addresses that have not been properly assigned.

DHCP snooping can be a valuable security measure, especially in larger networks where there may be multiple DHCP servers. By ensuring that only legitimate DHCP servers are allowed to hand out IP addresses, DHCP snooping can help prevent malicious devices from gaining access to the network or from causing problems for other devices on the network.

The Difference Between DHCP and DHCP Snooping

The main difference between DHCP and DHCP snooping is that DHCP snooping can help to prevent malicious DHCP servers from providing incorrect IP address information to clients. This is because DHCP snooping will only allow DHCP messages from known, trusted DHCP servers on the network to be forwarded to clients. It also helps to limit the amount of dhcp traffic on a network by rate-limiting dhcp requests.

Advantages and Disadvantages of DHCP Snooping

When it comes to DHCP, there are advantages and disadvantages to using DHCP snooping. Advantages include the fact that DHCP snooping can help to prevent malicious users from spoofing DHCP servers and gaining access to your network. It can also help to protect against denial-of-service attacks. Disadvantages of DHCP snooping include the fact that it can add complexity to your network and can cause problems with some applications.

How to Secure Your Network with DHCP Snooping

In order to secure your network with DHCP snooping, you will need to enable it on your devices and configure it properly. DHCP snooping helps to prevent malicious users from spoofing DHCP servers and gaining access to your network. It does this by checking the source of DHCP packets and only allowing packets from trusted sources.

When configuring DHCP snooping, you will need to specify the trusted interfaces that are allowed to send DHCP packets. These are typically the interfaces that connect to your legitimate DHCP servers. You will also need to specify any untrusted interfaces, which are typically those that connect to users’ computers. Once you have configured DHCP snooping, it will start checking all DHCP packets and only allow those from trusted sources.

If you want to further secure your network, you can also enable dynamic ARP inspection (DAI). DAI prevents attackers from spoofing ARP messages and gaining access to your network. It does this by checking the source of ARP packets and only allowing packets from trusted sources.

You can enable both DHCP snooping and DAI on most Cisco devices by using the following commands:

ip dhcp snooping

ip dhcp snooping vlan

ip dhcp snooping verify mac-address


ip dhcp snooping trust/disable


In conclusion, DHCP and DHCP Snooping are two powerful tools that can help secure your network from malicious attacks. By understanding how these protocols work, you can configure them to make sure that devices on your network are receiving the correct IP address and locking down any unauthorized connections. With a few simple steps, you will be able to protect your network from any potential threats.