Server Identifier

Code

54

Length

Fixed, 4 octets.

Value

A single, signed 32-bit IP address that identifies the DHCP server.

Description

This option is used in DHCPOffer and DHCPRequest messages and sometimes appears in DHCP Acknowledgment messages (DHCPAck, DHCPNak). The server identifier is the IP address of a selected DHCP server. This option type is used in two possible ways. First, servers include this option type in DHCPOffer messages so that clients can distinguish between multiple lease offers.

Second, clients include this option type in DHCPRequest messages to select a lease and indicate which offer is accepted from multiple lease offers. Also, clients can use the contents of this field for unicast sending of request messages to specific DHCP servers to renew a current lease.

Structure