RFC 1533 (rfc1533) - Page 3 of 30
DHCP Options and BOOTP Vendor Extensions
Alternative Format: Original Text Document
RFC 1533 DHCP Options and BOOTP Vendor Extensions October 1993
Any options defined subsequent to this document should contain a
length octet even if the length is fixed or zero.
All multi-octet quantities are in network byte-order.
When used with BOOTP, the first four octets of the vendor information
field have been assigned to the "magic cookie" (as suggested in RFC
951). This field identifies the mode in which the succeeding data is
to be interpreted. The value of the magic cookie is the 4 octet
dotted decimal 99.130.83.99 (or hexadecimal number 63.82.53.63) in
network byte order.
All of the "vendor extensions" defined in RFC 1497 are also DHCP
options.
Option codes 128 to 254 (decimal) are reserved for site-specific
options.
Except for the options in section 9, all options may be used with
either DHCP or BOOTP.
Many of these options have their default values specified in other
documents. In particular, RFC 1122 [4] specifies default values for
most IP and TCP configuration parameters.
3. RFC 1497 Vendor Extensions
This section lists the vendor extensions as defined in RFC 1497.
They are defined here for completeness.
3.1. Pad Option
The pad option can be used to cause subsequent fields to align on
word boundaries.
The code for the pad option is 0, and its length is 1 octet.
Code
+-----+
| 0 |
+-----+
Alexander & Droms