Vendor-Specific Information

Code

43

Length

Variable; minimum length is 1 octet.

Value

An object of n octets (where n is equal to the length specified with this option). The definition of values stored for this option type is vendor specific, and values provided here are presumed to be interpreted by vendor-specific code on DHCP clients and the DHCP server.

Description

This option is used by clients and servers to exchange vendor-specific information. Servers that are not equipped to interpret the information ignore it. Clients that expect but don't receive the information attempt to operate without it.

In some cases, a vendor uses this option type to send more than one information item; therefore, this option can serve as an encapsulated options subfield for encapsulating vendor-specific options. When encapsulating options, DHCP servers maintain the same syntax (that is, the same code/length/value fields sequence) for each encapsulated option type as it would normally appear in the full standard options field, with the following exceptions for the encapsulated vendor-specific subfield:

"Magic cookies" cannot be used.

All standard option codes—other than the padding option (0) or the end option (255)—can be redefined.

If present, the end option (255) signifies the end of the encapsulated vendor options, but not the end of the encapsulated vendor-specific subfield. If no end option is present, the end for the encapsulated vendor-specific subfield is taken from its stated length.

Structure

When this option type uses an encapsulated vendor-specific subfield, the information bytes 1– n have the following format: