BOOTPTAB(5)               System File Formats Manual               BOOTPTAB(5)

NAME
     bootptab - Internet Bootstrap Protocol server database

DESCRIPTION
     The bootptab file is the configuration database file for bootpd, the
     Internet Bootstrap Protocol server.  Its format is similar to that of
     termcap(5) in which two-character case-sensitive tag symbols are used to
     represent host parameters.  These parameter declarations are separated by
     colons (:), with a general format of:

           hostname:tg=value:tg=value:tg=value:

     where hostname is the actual name of a bootp client (or a "dummy entry"),
     and tg is a two-character tag symbol.  Replies are returned to clients
     only if an entry with the client's Ethernet or IP address exists in the
     booptab file.  Dummy entries have an invalid hostname (one with a "." as
     the first character) and are used to provide default values used by other
     entries via the tc=.dummy-entry mechanism.  Most tags must be followed by
     an equal sign and a value as above.  Some may also appear in a boolean
     form with no value (i.e. :tg:).

     The currently recognized tags are:

     bf   Bootfile

     bs   Bootfile size in 512-octet blocks

     cs   Cookie server address list

     df   Merit dump file

     dn   Domain name

     ds   Domain name server address list

     ef   Extension file

     gw   Gateway address list

     ha   Host hardware address

     hd   Bootfile home directory

     hn   Send client's hostname to client

     ht   Host hardware type (see Assigned Numbers RFC)

     im   Impress server address list

     ip   Host IP address

     lg   Log server address list

     lp   LPR server address list

     ns   IEN-116 name server address list

     nt   NTP (time) Server (RFC 1129)

     ra   Reply address override

     rl   Resource location protocol server address list

     rp   Root path to mount as root

     sa   TFTP server address client should use

     sm   Host subnet mask

     sw   Swap server address

     tc   Table continuation (points to similar "template" host entry)

     td   TFTP root directory used by "secure" TFTP servers

     to   Time offset in seconds from UTC

     ts   Time server address list

     vm   Vendor magic cookie selector

     yd   YP (NIS) domain name

     ys   YP (NIS) server address

     There is also a generic tag, where n is an RFC1084 vendor field tag num-
     ber.  Thus it is possible to immediately take advantage of future exten-
     sions to RFC1084 without being forced to modify bootpd first.  Generic
     data may be represented as either a stream of hexadecimal numbers or as a
     quoted string of ASCII characters.  The length of the generic data is
     automatically determined and inserted into the proper field(s) of the
     RFC1084-style bootp reply.

     The following tags take a whitespace-separated list of IP addresses: cs,
     ds, gw, im, lg, lp, ns, nt, ra, rl, and ts.

     The ip, sa, sw, sm, and ys tags each take a single IP address.  All IP
     addresses are specified in standard Internet "dot" notation and may use
     decimal, octal, or hexadecimal numbers (octal numbers begin with 0, hex-
     adecimal numbers begin with '0x' or '0X').  Any IP addresses may alterna-
     tively be specified as a hostname, causing bootpd to lookup the IP
     address for that host name using gethostbyname(3).  If the ip tag is not
     specified, bootpd will determine the IP address using the entry name as
     the host name.  (Dummy entries use an invalid host name to avoid auto-
     matic IP lookup.)

     The ht tag specifies the hardware type code as either an unsigned deci-
     mal, octal, or hexadecimal integer or one of the following symbolic
     names: ethernet or ether for 10Mb Ethernet, ethernet3 or ether3 for 3Mb
     experimental Ethernet, ieee802, tr, or token-ring for IEEE 802 networks,
     pronet for Proteon ProNET Token Ring, or chaos, arcnet, or ax.25 for
     Chaos, ARCNET, and AX.25 Amateur Radio networks, respectively.  The ha
     tag takes a hardware address which may be specified as a host name or in
     numeric form.  Note that the numeric form must be specified in hexadeci-
     mal; optional periods and/or a leading '0x' may be included for readabil-
     ity.  The ha tag must be preceded by the ht tag (either explicitly or
     implicitly; see tc below).  If the hardware address is not specified and
     the type is specified as either "ethernet" or "ieee802", then bootpd will
     try to determine the hardware address using ether_hostton(3).

     The hostname, home directory, and bootfile are ASCII strings which may be
     optionally surrounded by double quotes (").  The client's request and the
     values of the hd and bf symbols determine how the server fills in the
     bootfile field of the bootp reply packet.

     If the bf option is specified, its value is copied into the reply packet.
     Otherwise, the name supplied in the client request is used.  If the hd
     option is specified, its value is prepended to the boot file in the reply
     packet, otherwise the path supplied in the client request is used.  The
     existence of the boot file is NOT verified by bootpd because the boot
     file may be on some other machine.

     The bs option specified the size of the boot file.  It can be written as
     bs=auto which causes bootpd to determine the boot file size automati-
     cally.

     Some newer versions of tftpd(8) provide a security feature to change
     their root directory using the chroot(2) system call.  The td tag may be
     used to inform bootpd of this special root directory used by (One may
     alternatively use the bootpd "-c chdir" option.)  The hd tag is actually
     relative to the root directory specified by the td tag.  For example, if
     the real absolute path to your BOOTP client bootfile is /tftpboot/boot-
     files/bootimage, and tftpd uses /tftpboot as its "secure" directory, then
     specify the following in bootptab:

           :td=/tftpboot:hd=/bootfiles:bf=bootimage:

     If your bootfiles are located directly in /tftpboot, use:

           :td=/tftpboot:hd=/:bf=bootimage:

     The sa tag may be used to specify the IP address of the particular TFTP
     server you wish the client to use.  In the absence of this tag, bootpd
     will tell the client to perform TFTP to the same machine bootpd is run-
     ning on.

     The time offset to may be either a signed decimal integer specifying the
     client's time zone offset in seconds from UTC, or the keyword auto which
     uses the server's time zone offset.  Specifying the to symbol as a
     boolean has the same effect as specifying auto as its value.

     The bootfile size bs may be either a decimal, octal, or hexadecimal inte-
     ger specifying the size of the bootfile in 512-octet blocks, or the key-
     word auto which causes the server to automatically calculate the bootfile
     size at each request.  As with the time offset, specifying the bs symbol
     as a boolean has the same effect as specifying auto as its value.

     The vendor magic cookie selector (the vm tag) may take one of the follow-
     ing keywords: auto (indicating that vendor information is determined by
     the client's request), rfc1048 or rfc1084 (which always forces an
     RFC1084-style reply), or cmu (which always forces a CMU-style reply).

     The hn tag is strictly a boolean tag; it does not take the usual equals-
     sign and value.  It's presence indicates that the hostname should be sent
     to RFC1084 clients.  Bootpd attempts to send the entire hostname as it is
     specified in the configuration file; if this will not fit into the reply
     packet, the name is shortened to just the host field (up to the first
     period, if present) and then tried.  In no case is an arbitrarily-trun-
     cated hostname sent (if nothing reasonable will fit, nothing is sent).

     Often, many host entries share common values for certain tags (such as
     name servers, etc.).  Rather than repeatedly specifying these tags, a
     full specification can be listed for one host entry and shared by others
     via the tc (table continuation) mechanism.  Often, the template entry is
     a dummy host which doesn't actually exist and never sends bootp requests.
     This feature is similar to the tc feature of termcap(5) for similar ter-
     minals.  Note that bootpd allows the tc tag symbol to appear anywhere in
     the host entry, unlike termcap which requires it to be the last tag.
     Information explicitly specified for a host always overrides information
     implied by a tc tag symbol, regardless of its location within the entry.
     The value of the tc tag may be the hostname or IP address of any host
     entry previously listed in the configuration file.

     Sometimes it is necessary to delete a specific tag after it has been
     inferred via tc.  This can be done using the construction which removes
     the effect of tag as in termcap(5).  For example, to completely undo an
     IEN-116 name server specification, use ":ns@:" at an appropriate place in
     the configuration entry.  After removal with @, a tag is eligible to be
     set again through the tc mechanism.

     Blank lines and lines beginning with "#" are ignored in the configuration
     file.  Host entries are separated from one another by newlines; a single
     host entry may be extended over multiple lines if the lines end with a
     backslash (\).  It is also acceptable for lines to be longer than 80
     characters.  Tags may appear in any order, with the following exceptions:
     the hostname must be the very first field in an entry, and the hardware
     type must precede the hardware address.

     An example /etc/bootptab file follows:

                # Sample bootptab file (domain=andrew.cmu.edu)

                .default:\
                     :hd=/usr/boot:bf=null:\
                     :ds=netserver, lancaster:\
                     :ns=pcs2, pcs1:\
                     :ts=pcs2, pcs1:\
                     :sm=255.255.255.0:\
                     :gw=gw.cs.cmu.edu:\
                     :hn:to=-18000:

                carnegie:ht=6:ha=7FF8100000AF:tc=.default:
                baldwin:ht=1:ha=0800200159C3:tc=.default:
                wylie:ht=1:ha=00DD00CADF00:tc=.default:
                arnold:ht=1:ha=0800200102AD:tc=.default:
                bairdford:ht=1:ha=08002B02A2F9:tc=.default:
                bakerstown:ht=1:ha=08002B0287C8:tc=.default:

                # Special domain name server and option tags for next host
                butlerjct:ha=08002001560D:ds=128.2.13.42:\
                     :T37=0x12345927AD3BCF:\
                     :T99="Special ASCII string":\
                     :tc=.default:

                gastonville:ht=6:ha=7FFF81000A47:tc=.default:
                hahntown:ht=6:ha=7FFF81000434:tc=.default:
                hickman:ht=6:ha=7FFF810001BA:tc=.default:
                lowber:ht=1:ha=00DD00CAF000:tc=.default:
                mtoliver:ht=1:ha=00DD00FE1600:tc=.default:

FILES
           /etc/bootptab   file describing allowable connections

SEE ALSO
     bootpd(8), tftpd(8)

     DARPA Internet Request For Comments RFC951, RFC1048, RFC1084, Assigned
     Numbers

Interix                          May 21, 2009                          Interix