What is DHCP?

    DHCP (Dynamic Host Configuration Protocol) is a network protocol that enables a DHCP server to automatically assign an IP address to an individual computer's TCP/IP stack software. DHCP assigns a number dynamically from a defined range of numbers (i.e., a scope) configured for a given network.

    Client computers configured to use DHCP for IP assignment do not need to have a statically assigned IP address. In addition, they generally do not need to have addresses configured for DNS servers or WINS servers, as the DHCP server also sets these.

    DHCP assigns a TCP/IP address when a system is started. Typically, it works like this:

  • A user turns on a computer with a DHCP client.

  • The client computer sends a broadcast request (called a DISCOVER), looking for a DHCP server to answer.

  • The router directs the computer to the correct DHCP server.

  • The server sends a DHCP OFFER packet.

  • The client sends a DHCP REQUEST packet.

  • The client sends a DHCP ACK packet.

  • The server assigns an IP number according to the scope range defined on the server. The server also configures the client's DNS servers, WINS servers, NTP servers, and sometimes other services as well.

    Currently, most of the IP addresses at IU are assigned statically; that is, the individual computer is manually configured to use a specific assigned IP. One problem of static assignment, resulting from user error or inattention to detail, occurs when two computers are configured with the same IP number. This creates a conflict that results in loss of service. Using DHCP to dynamically assign IPs minimizes these conflicts.


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