DHCP snooping

In computer networking, DHCP snooping is a series of techniques applied to improve the security of a DHCP infrastructure.^[1]

Example showing how DHCP snooping works

DHCP servers allocate IP addresses to clients on a LAN. DHCP snooping can be configured on LAN switches to exclude rogue DHCP servers and remove malicious or malformed DHCP traffic. In addition, information on hosts which have successfully completed a DHCP transaction is accrued in a database of bindings which may then be used by other security or accounting features.^[2][3]

Other features may use DHCP snooping database information to ensure IP integrity on a Layer 2 switched domain. This information enables a network to:

• Track the physical location of IP addresses when combined with AAA accounting or SNMP.
• Ensure that hosts only use the IP addresses assigned to them when combined with source-guard a.k.a. source-lockdown^[4]
• Sanitize ARP requests when combined with arp-inspection a.k.a. arp-protect