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 This document will be periodically superseded by later documents defining new vendor extensions.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]