DHCP - Options

DHCP (Dynamic Host Configuration Protocol) options are a set of configurable parameters that a DHCP server can deliver to clients during the DHCP lease negotiation process. These options allow the DHCP server to provide clients with additional configuration information beyond just an IP address, such as network-specific settings.

When a DHCP client requests an IP address, the DHCP server responds not only with the IP address but also with any other necessary configuration options. These options are included in the DHCP offer message sent by the server to the client. The client can then use this information to configure its network interface.

There are over 130 officially assigned DHCP option codes, ranging from 0 to 255. These option codes are standardized and managed by the Internet Assigned Numbers Authority (IANA).

IP phones typically use a whole series of DHCP options for their configuration and operation.

Links

https://www.iana.org/assignments/bootp-dhcp-parameters/bootp-dhcp-parameters.xhtml