Internet Engineering Task Force R. Droms
INTERNET-DRAFT Bucknell University
June, 1992
DHCP Vendor Extensions
1 Abstract
The Dynamic Host Configuration Protocol (DHCP) passes network configuration
information to hosts on a TCP/IP network. This document defines the vendor
extenstions that may appear in the 'vend' field in a DHCP message.
This document will be periodically superseded by later documents defining
new vendor extensions. Each later document will include the entire current
list of valid vendor extensions.
2 Status of this memo
This draft document is a product of the IETF Dynamic Host Configuration
Working Group. Distribution of this memo is unlimited. Please respond with
comments to the host-conf@sol.cs.bucknell.edu mailing list. This document
will expire on January 1, 1993.
This document is an Internet Draft. Internet Drafts are working documents
of the Internet Engineering Task Force (IETF), its Areas, and its Working
Groups. Note that other groups may also distribute working documents as
Internet Drafts.
Internet Drafts are draft documents valid for a maximum of six months.
Internet Drafts may be updated, replaced, or obsoleted by other documents
at any time. It is not appropriate to use Internet Drafts as reference
material or to cite them other than as a ``working draft'' or ``work
in progress.'' Please check the 1id-abstracts.txt listing contained
in the internet-drafts Shadow Directories on nic.ddn.mil, nnsc.nsf.net,
nic.nordu.net, ftp.nisc.sri.com, or munnari.oz.au to learn the current
Status Of Any Internet Draft.
INTERNET-DRAFT DHCP Vendor Extensions June, 1992
3 DHCP Vendor Extension Fields
The field formats are defined as in RFC 1084. Each data field consists of
a tag octet, a length octet (n in the following table) and length octets
of data. The last column in the table gives the total number of octets
required for the field, including the tag and length octets.
4 Security Considerations
This document does not address security issues.
5 Author's Address
Ralph Droms
Computer Science Department
323 Dana Engineering
Bucknell University
Lewisburg, PA 17837
(717) 524--1145
droms@bucknell.edu
6 Expiration date
This document will expire on January 1, 1993.
R. Droms [Page 2]
INTERNET-DRAFT DHCP Vendor Extensions June, 1992
Vendor_extensions_from_RFC_1084:_
Pad 0 [1]
End 255 [1]
Subnet mask 1 address [6]
Time offset 2 long [6]
Router 3 n/4 addrs [n+2]
Time servers (RFC 868) 4 n/4 addrs [n+2]
IEN--116 name servers 5 n/4 addrs [n+2]
Domain name servers 6 n/4 addrs [n+2]
Log servers 7 n/4 addrs [n+2]
Cookie/quote servers (RFC 865) 8 n/4 addrs [n+2]
lpr (BSD printer) servers 9 n/4 addrs [n+2]
Impress servers 10 n/4 addrs [n+2]
RLP servers (RFC 887) 11 n/4 addrs [n+2]
Host name 12 n octets [n+2]
Boot file size 13 short [4]
Reserved tags (site--specific) 128--254
IP--layer_parameters,_per_host:_
Be a router 20 0/1 [3]
Non--local source routing 21 0/1 [3]
Policy filters for 22 n octets of filters [n+2]
non--local source routing
Maximum reassembly size 23 short [4]
Default TTL 24 octet [3]
PMTU aging timeout 25 long (?) [6]
PMTU plateau table 26 n octets [n+2]
IP--layer_parameters,_per_interface:_
MTU 29 short [4]
All--subnets--MTU 30 0/1 [3]
Broadcast address 31 0/1 [3]
(0 == all 0s,
1 == all 1s)
Perform mask discovery 32 0/1 [3]
Be a mask supplier 33 0/1 [3]
Perform router discovery 34 0/1 [3]
Router solicitation address 35 address [6]
Static routes 37 n octets [n+2]
R. Droms [Page 3]
INTERNET-DRAFT DHCP Vendor Extensions June, 1992
Link--layer_parameters,_per_interface:_
Trailers 38 0/1 [3]
Arp cache timeout 39 long [6]
Ethernet encapsulation 40 (RFC894/1042) [4]
TCP_parameters,_per_host:_
TTL 41 octet [3]
Keep--alive interval 42 long [6]
Keep--alive data size 43 0/1 [3]
Other_extensions:_
Requested IP address 46 address [6]
IP address lease time 47 long [6]
Use 'file'/'sname' fields 49 1='file' [3]
2='sname'
3=both
DHCP message type 51 1=DHCPDISCOVER [3]
2=DHCPOFFER
3=DHCPREQUEST
4=DHCPDECLINE
5=DHCPACK
6=DHCPNAK
7=DHCPRELEASE
Lease identifier cookie 52 n octets [n+2]
Server identifier 53 address [6]
Parameter request vector 54 256 bit (32 octet) vector [34]
Parameter request list 55 n parameter tags [n+2]
The bit--order is big--endian within
octets. The bit for parameter 0 is the
high--order bit of the first octet.
NIS (YP) domain 56 n octets [n+2]
NIS (YP) servers 57 n/4 addresses [n+2]
NTP (RFC1129) servers 58 n/4 addresses [n+2]
Message 59 n octets of NVT ASCII text [n+2]
Maximum DHCP message size 60 short [3]
R. Droms [Page 4]
INTERNET-DRAFT DHCP Vendor Extensions June, 1992
The following table gives interpretations for some vendor extensions:
Requested IP address A hint from the client to the
server as to the client's preferred
IP address
IP address lease time Duration of time over which allo-
cated IP address may be used
Use 'file'/'sname' fields Use 'file' and/or 'sname' fields
as extensions to the 'vend' field.
If both 'file' and 'sname' are
specified, use the 'file' field
first
DHCP message type Type of the DHCP message
Lease identifier cookie Unique identifier for lease that
applies to the IP address in the
DHCP message
Server identifier IP address of server that allocated
the IP address
Parameter request vector Bit vector identifying DHCP parame-
ters requested by client
Parameter request list List of vendor extension identi-
fiers of parameters requested by
client
NIS (YP) domain NIS (YP) domain for the client
NIS (YP) servers List of NIS (YP) servers for the
client
NTP (RFC1129) servers List of NTP servers for the client
Message ASCII text of message intended
for display to user on client as
diagnostic message from server
Maximum DHCP message size Maximum DHCP message (including IP
and UDP headers) this client is
prepared to receive
R. Droms [Page 5]