option vendor-class-identifier string;

This option is used by some DHCP clients to identify the vendor type and possibly the configuration of a DHCP client. The information is a string of bytes whose contents are specific to the vendor and are not specified in a standard. To see what vendor class identifier clients are sending, you can write the following in your DHCP server configuration file:

set vendor-class option vendor-class-identifier;

This will result in all entries in the DHCP server lease database file for clients that sent vendor-class-identifier options having a set statement that looks something like this:

set vendor-class "SUNW.Ultra-5_10";

The vendor-class-identifier option is normally used by the DHCP server to determine the options that are returned in the vendor-encapsulated-options option.