bionic (5) bootptab.5.gz

Provided by: bootp_2.4.3-18build1_amd64 bug

NAME

       bootptab - Internet Bootstrap Protocol server database

DESCRIPTION

       The  bootptab file is the configuration database file for bootpd, the Internet Bootstrap Protocol server.
       It's 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.   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  equals-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
            dl   DHCP lease time in seconds
            dn   Domain name
            ds   Domain name server address list
            ef   Extension file
            ex   York ex option (huh?)
            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
            ms   Message size
            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, Tn, where n is an RFC1084 vendor field tag number.  Thus it is  possible  to
       immediately  take  advantage of future extensions 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, hexadecimal numbers begin with '0x' or '0X').  Any IP addresses may alternatively
       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 automatic IP lookup.)

       The ht tag specifies the hardware type code as either an unsigned decimal, 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 hexadecimal; optional periods and/or a leading '0x' may be included for
       readability.  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_hton(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 client provides a file name it is left as is.  Otherwise, if the bf option is specified its  value
       is  copied  into  the reply packet.  If the hd option is specified as well, its value is prepended to the
       boot file copied into the reply packet.  The existence of the boot file is checked only  if  the  bs=auto
       option  is  used  (to  determine  the  boot file size).  A reply may be sent whether or not the boot file
       exists.

       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
       tftpd.  (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/bootfiles/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 running 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 integer specifying the size of the
       bootfile in 512-octet blocks, or the keyword 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 following  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 (including domain) 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-truncated 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  terminals.  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 tag@ 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
              The definition file

SEE ALSO

       bootpd(8), tftpd(8),
       DARPA Internet Request For Comments RFC951, RFC1048, RFC1084, Assigned Numbers