1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
|
To: iana@isi.edu
Subject: Request for three DHCP option numbers
Date: Mon, 11 Nov 1996 16:35:13 -0500
From: Ralph E. Droms <droms@charcoal.eg.bucknell.edu>
An Extension to the DHCP Option Codes
<draft-ietf-dhc-options-opt127-02.txt>
The Dynamic Host Configuration Protocol (DHCP) [1] provides a
framework for passing configuration information to hosts on a TCP/IP
network. Configuration parameters and other control information are
carried in tagged data items that are stored in the 'options' field
of the DHCP message. The data items themselves are also called
"options."
Each option is assigned a one-octet option code. Options 128-254 are
reserved for local use and at this time over half of the available
options in the range 0-127 and option 255 have been assigned. This
document defines a new option to extend the available option codes
and new option to request the parameters represented by those new
option codes.
Definition of option 127
Option code 127 indicates that the DHCP option has a two-octet
extended option code. The format of these options is:
Extended
Code Len option code Data...
+-----+-----+-----+-----+-----+-----+----
| 127 | XXX | oh | ol | d1 | d2 | ...
+-----+-----+-----+-----+-----+-----+----
Definition of option 126
This option is used by a DHCP client to request values for specified
configuration paramaters that are identified by extended option codes
as defined above. The list of n requested parameters is specified as
2n octets, where each pair of octets is a valid extended option code.
The client MAY list the options in order of preference. The DHCP
server is not required to return the options in the requested order,
but MUST try to insert the requested options in the order requested
by the client.
The code for this option is 126. Its minimum length is 2.
Extended
Code Len option codes
+-----+-----+-----+-----+-----+-----+----
| 126 | XXX | c1h | c1l | c2h | c2l | ...
+-----+-----+-----+-----+-----+-----+----
|
