Provided by: bootp_2.4.3-19.1_amd64 bug


       bootptab - Internet Bootstrap Protocol server database


       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:


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


       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 (

                 :ds=netserver, lancaster:\
                 :ns=pcs2, pcs1:\
                 :ts=pcs2, pcs1:\


            # Special domain name server and option tags for next host
                 :T99="Special ASCII string":\



              The definition file


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