NAME | DESCRIPTION | OPTIONS | USAGE | FILES | ATTRIBUTES | SEE ALSO
For the most part, parameters (henceforth referred to as options) returned to the client by the DHCP/BOOTP protocol are encoded in the so-called vendor field of the BOOTP packet. Each option is identified numerically, and also carries a length specifier. The purpose of dhcptags is to indentify the type of each option, to label each with a short mnemonic text string for use by dhcpinfo(1), and to give a longer textual description.
Options defined by DHCP are of three general types:
All client and server DHCP implementations agree on the semantics. These are administered by the Internet Naming Authority (IANA). These options are numbered from 1 to 127.
Within a specific site, all client and server implementations agree as to the semantics. However, at another site the type and meaning of the option may be quite different. These options are numbered from 128 to 254.
Each vendor may define 256 options unique to that vendor. The vendor is identified within a DHCP packet by the "Vendor Class" option (#60). An option with a specific numeric identifier belonging to one vendor will, in general, have a type and semantics different from that of a different vendor. Vendor options are "super-encapsulated" into the vendor field (#43); within a specific DHCP packet there may be several instances of option #43.
As well as the three general types, the Solaris DHCP implementation defines certain "pseudo" options, numbered from 512 upward. These are a convenient method for referring to items which either correspond to fixed fields in the BOOTP packet (such as the siaddr field) or which, though not options themselves, are used in constructing valid options (for example, the home directory used in constructing the exact path to a boot image).
In general, the agent (see dhcpagent(1M)) knows little if anything about the semantics of any of the first three kinds of option, except for the subnet mask and broadcast address. Its only duty is to acquire and store this data and to make it available to other interested parties (see dhcpinfo(1)). The responsibility for understanding and using the data rests with these third parties. Pseudo tags, on the contrary, have a specific meaning to dhcpagent(1M), and consequently it is meaningless to add to this list. The only useful edit that can be performed on the pseudo tags is to change the textual description or the mnemonic.
Blank lines and those whose first non-whitespace character is '#' are ignored. Data entries are written one per line and have five fields. An individual entry cannot be continued onto another line.
The fields are (in order):
Tag number
Mnemonic identifier
Vendor class
(One from the following case insensitive values):
A 1-byte value
A 2-byte value
A 4-byte value
A printable character string
An IP address
A list of IP addresses
A list of 2-byte values
An array of 1-byte values
Either true or false
Long name
Table of Standard Tags | |||
---|---|---|---|
Tag Number | Identifier | Data Type | Description |
1 | NetMask | ip | Subnet mask |
2 | UTCoffst | time | Time offset from GMT |
3 | Router | iplist | IP addresses of routers |
4 | Timeserv | iplist | IP addresses of time servers |
5 | IEN116ns | iplist | IP addresses of IEN=116 name servers |
6 | DNSserv | iplist | IP addresses of domain name servers |
7 | Logserv | iplist | IP addresses of remote logging servers |
8 | Cookie | iplist | IP address list of fortune cookie servers |
9 | Lprserv | iplist | IP address list of print servers |
10 | Impress | iplist | IP address list of impress servers |
11 | Resource | iplist | IP address list of RLP servers |
12 | Hostname | string | hostname (or nodename) of client |
13 | Bootsize | int16 | size (in 512 blocks) of client boot file |
14 | Dumpfile | string | path name of Merit dump file |
15 | DNSdmain | string | DNS domain name |
16 | Swapserv | ip | ip address of swap file server |
17 | Rootpath | ip | |
18 | ExtendP | string | |
19 | IPFwdF | boolean | Enable IP forwarding |
20 | NLrouteF | boolean | |
21 | PFilter | iplist | IP address list of policy filter servers |
22 | MaxIpSiz | int16 | Maximum reassembly size of IP datagram |
23 | IpTTL | byte | IP time-to-live field |
24 | PathTO | time | PMTU timeout |
25 | PathTbl | int16list | PMTU plateaus |
26 | MTU | int16 | Maximum transmission unit |
27 | SameMtuF | boolean | Subnets are local |
28 | Broadcst | ip | IP broadcast address of interface |
29 | MaskDscf | boolean | When true perform mask discovery |
30 | MaskSupF | boolean | When true supply subnet masks |
31 | RDiscvyF | boolean | Perform route discovery |
32 | RsolictS | ip | IP address for router solicitation |
33 | StaticRt | iplist | Pairs of IP addresses for all static routes |
34 | TrailerF | boolean | Perform trailer encapsulation |
35 | ArpTimeO | time | Timeout interval for entry in ARP cache |
36 | EthEncap | boolean | Perform Ethernet encapsulation |
37 | TcpTTL | byte | TCP time-to-live |
38 | TcpKaInt | time | TCP keep alive interval |
39 | TcpKaGbF | boolean | Send TCP keep alive garbage octet |
40 | NISdmain | string | NIS domain name |
41 | NISservs | iplist | IP address list of NIS servers |
42 | NTPservs | iplist | IP address list of NTP servers |
44 | NetBNms | iplist | IP address list of NetBios name servers |
45 | NetBDsts | iplist | IP address list of NetBios DG servers |
46 | NetBNdT | byte | NetBios node type |
47 | NetBScop | string | NetBios scope |
48 | XFontSrv | iplist | IP address list of X font servers |
49 | XDispMgr | iplist | IP address list of X display managers |
50 | RequestIP | ip | IP address requested by client |
51 | LeaseTim | time | Lease duration (secs) |
52 | Overload | byte | File and/or sname fields overloaded |
53 | MsgType | byte | DHCP message type |
54 | ServerIp | ip | IP address of DHCP server selected by client |
55 | rv | opaque | DHCP options requested by client |
56 | Message | string | Message from DHCP server to client |
57 | MaxMsgSz | byte | Maximum BOOTP message size acceptable |
58 | T1Time | time | DHCP renewal interval |
59 | T2Time | time | DHCP rebind interval |
60 | Vendor | string | Client's vendor class |
61 | ClientID | opaque | Client identifier |
62 | NW_domain | string | Netware domain |
63 | NWIPopts | string | Netware options |
64 | NIS+dom | string | NIS+ domain name |
65 | NIS+serv | iplist | IP address list of NIS+ servers |
66 | TFTPsrvN | string | Boot file server name |
67 | OptBootF | string | Path to boot file on boot file server |
68 | MblIPAgt | iplist | IP address list of mobile IP home agents |
69 | SMTPserv | iplist | IP address list of SMTP servers |
70 | POP3serv | iplist | IP address list of POP servers |
71 | NNTPserv | iplist | IP address list of NNTP servers |
72 | WWWsertvs | iplist | IP address list of WWW servers |
73 | Finfgersv | iplist | IP address list of Finger servers |
74 | IRCservs | iplist | IP address list of IRC servers |
75 | STservs | iplist | IP address list of StreetTalk servers |
76 | STDAservs | iplist | IP address list of STDA servers |
77 | UserClass | string | Client's user class |
See attributes(5) for descriptions of the following attributes:
ATTRIBUTE TYPE | ATTRIBUTE VALUE |
Availability | SUNWcsr |
dhcpinfo(1), dhcpagent(1M), attributes(5)
Alexander, S., and R. Droms, DHCP Options and BOOTP Vendor Extensions, RFC 2132, Silicon Graphics, Inc., Bucknell University, March 1997.
Droms, R., Dynamic Host Configuration Protocol, RFC 2131, Bucknell University, March 1997.
NAME | DESCRIPTION | OPTIONS | USAGE | FILES | ATTRIBUTES | SEE ALSO