Table 192: DHCP/BOOTP Options: RFC 1497 Vendor Extensions
Code Value
|
Data Length
(bytes)
|
Name
and Description
|
0
|
0
|
Pad: A single byte
used as filler to align a subsequent field on a word (two-byte)
boundary. Contains no information.
One of two options that is a single byte in length, having no Data
subfield (the other being the End option below.)
|
1
|
4
|
Subnet
Mask: A 32-bit subnet
mask being supplied for the client to
use on the current network. Must appear in the option list before the
Router option if both are present.
|
2
|
4
|
Time Offset: Specifies
the time offset of the client's subnet in seconds from Coordinated
Universal Time (UTC, formerly Greenwich Mean Time
or GMT). Positive values represent areas east of the prime meridian
(in the United Kingdom), negative values areas west. Essentially, this
is used to indicate the time zone of the subnet.
|
3
|
Variable
(Multiple of 4)
|
Router:
Specifies a list of 32-bit router addresses for the client to use on
the local network. Routers are listed in the order of preference for
the client to use.
|
4
|
Variable (Multiple
of 4)
|
Time Server: Specifies
a list of time server addresses (per
RFC 868) for the client to use on the
local network. Servers are listed in the order of preference for the
client to use.
|
5
|
Variable
(Multiple of 4)
|
IEN-116
Name Server: Specifies a list of IEN-116 name server addresses
for the client to use on the local network. Servers are listed in the
order of preference for the client to use.
Note that this option is not used for DNS name servers; see below.
|
6
|
Variable (Multiple
of 4)
|
DNS Name Server:
Specifies a list of DNS
name server addresses for the client to use on the local network. Servers
are listed in the order of preference for the client to use.
|
7
|
Variable
(Multiple of 4)
|
Log Server:
Specifies a list of MIT-LCS UDP log server addresses for the client
to use on the local network. Servers are listed in the order of preference
for the client to use.
|
8
|
Variable (Multiple
of 4)
|
Cookie Server:
Specifies a list of RFC
865 cookie server addresses
for the client to use on the local network. Servers are listed in the
order of preference for the client to use.
|
9
|
Variable
(Multiple of 4)
|
LPR Server:
Specifies a list of RFC 1179 line printer server addresses for the client
to use on the local network. Servers are listed in the order of preference
for the client to use.
|
10
|
Variable (Multiple
of 4)
|
Impress Server:
Specifies a list of Imagen Impress server addresses for the client to
use on the local network. Servers are listed in the order of preference
for the client to use.
|
11
|
Variable
(Multiple of 4)
|
Resource
Location Server: Specifies a list of RFC 887 resource location
server addresses for the client to use on the local network. Servers
are listed in the order of preference for the client to use.
|
12
|
Variable
|
Host Name: Specifies
a host name for the client. This may or may not be a DNS host name;
see option #15 below.
|
13
|
2
|
Boot
File Size: Specifies the size of the default boot image file
for the client, expressed in units of 512 bytes.
|
14
|
Variable
|
Merit Dump File:
Specifies the path and filename of the file to which the client should
dump its core image in the event that it crashes.
|
15
|
Variable
|
Domain
Name: Specifies the DNS domain name for the client. Compare
to option #12.
|
16
|
4
|
Swap Server: Specifies
the address of the client's swap server.
|
17
|
Variable
|
Root
Path: Specifies the path name of the client's root disk. This
allows the client to access files it may need, using a protocol such
as NFS.
|
18
|
Variable
|
Extensions Path:
Specifies the name of a file that contains vendor-specific fields that
the client can interpret in the same way as the Options or Vend
field in a DHCP/BOOTP message. This was defined to allow a client and
server to still exchange vendor-specific information even though the
Option/Vend field is now used for the general-purpose fields
described in this topic.
Also see option #43 below.
|
255
|
0
|
End:
Placed after all other options to mark the end of the option list.
One of two options that is a single byte in length, having no Data
subfield (the other being the Pad option above.)
|