DHCP (Dynamic Host Configuration Protocol) is a protocol that enables Network Administrators to manage Internet Protocol (IP) addresses from a central location. Using TCP/IP, each machine that connects to the network requires a unique IP address. Typically, when a Windows computer connects to a network, it first looks for a DHCP server to obtain an IP address. If it does not find the DHCP server, Windows uses APIPA (Automatic Private IP Addressing) to assign the computer an IP address. OPC communication will rarely work using an APIPA address, so users typically have to manually assign an IP address.

DHCP is an alternative to BOOTP (Bootstrap Protocol), which is another network IP management protocol. While DHCP is a more advanced protocol, both configuration management protocols are commonly used. In some cases, organizations use both protocols.

See also: APIPA, BOOTP, Internet Protocol (IP)