BOOTPTAB(5)							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 sepa-
       rated 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  cur-
       rently 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,  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  hexadeci-
       mal  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 speci-
       fied, 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 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 net-
       works,  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_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  auto-
       matically.

       Some  newer versions of tftpd 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  deter-
       mined  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-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 configura-
       tion 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 appro-
       priate 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

SEE ALSO

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

4.3 Berkeley Distribution					 October 31, 1991						       BOOTPTAB(5)