bootpd(1M)

NAME

bootpd − Internet Boot Protocol server

SYNOPSIS

/etc/bootpd [−t timeout] [−s] [−d debuglevel] [configfile [dumpfile]]

DESCRIPTION

bootpd implements an Internet Boot Protocol (BOOTP) server as defined in RFC951 and RFC1048. bootpd can be run either through inetd(1M) or as a stand-alone daemon. It is run by /etc/inetd when the following line in included the file /etc/inetd.conf:

bootps dgram udp wait root /etc/bootpd bootpd

bootpd starts when a boot request arrives. If bootpd does not receive another boot request within fifteen minutes of the last one received, it exits. The −t option can be used to specify a different timeout value in minutes (such as −t20). A timeout value of zero means that bootpd will never exit.

To run bootpd as a stand-alone daemon, invoke it with the −s option (for example, at boot time from /etc/netbsdsrc). This may be the desired mode of operation for large network installations with many BOOTP clients. In this case, the −t option has no effect since bootpd never exits.

The −d option sets the verbosity level of the logging emitted by the daemon.

Configuration

Upon startup, bootpd reads its configuration file, /etc/bootptab, or the configfile specified in the command line, then listens for boot request packets. bootpd rereads its configuration file when it receives a hangup signal, SIGHUP, or when it receives a boot request packet and detects that the file has been updated. If hosts are added, deleted or modified, their entries in bootpd’s internal database are updated accordingly when the configuration file is reread.

If bootpd receives a SIGUSR1 signal, it dumps its memory-resident database to the file /etc/bootpd.dump or the dumpfile specified in the command line.

The configuration file uses two-character, case-sensitive tag symbols to represent host parameters. These parameter declarations are separated by colons (:). The general format is:

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

where hostname is the actual name of a BOOTP client and tg is a two-character tag symbol. Most tags must be followed by an equals-sign and a value as above. Some can also appear in a boolean form with no value (i.e. :tg:).

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 can 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 can appear in any order with the following exceptions: the hostname must be the very first field in an entry, nd the hardware type tag, ht, must precede the hardware address tag, ha.

IP addresses are specified in standard Internet "dot" notation, and can use decimal, octal, or hexadecimal numbers (octal numbers begin with 0, hexadecimal numbers begin with 0x or 0X). Certain tags accept a list of one or more IP addresses (ip-address-list). When more than one IP address is listed, the addresses should be separated by white space.

The currently recognized tags are:

ba This tag specifies that bootpd should broadcast the boot reply to the client. As a boolean tag, it causes bootpd to send the boot reply on the configured broadcast address of each network interface. You can also assign the tag an ip-address value which specifies the specific IP or broadcast address for the boot reply. The ba tag should only be used for diagnostic purposes; e.g., for debugging boot replies with bootpquery(1M).

bf=filename
This tag specifies the filename of the bootfile which the client should download via TFTP. The client’s boot request and the values of the hd (see below) and bf symbols determine how the server fills in the bootfile field of the boot reply packet.

If the client specifies an absolute pathname and that file exists on the server machine, that pathname is returned in the reply packet. If the file cannot be found, the request is discarded; no reply is sent. If the client specifies a relative pathname, a full pathname is formed by appending the pathname to the value of the hd tag and testing for existence of the file. If the resulting boot file pathname cannot be found, the request is discarded.

Clients that do not specify boot files in their boot requests will always elicit a reply from the server. The exact reply will again depend upon the hd and bf tags. If the bf tag gives an absolute pathname and the file exists, that pathname is returned in the reply packet. Otherwise, if the hd and bf tags together specify an accessible file, that filename is returned in the reply. If a complete filename cannot be determined or the file does not exist, the reply will contain a zeroed-out bootfile field.

tftpd(1m) performs a chroot(2) to the home directory of the pseudo-user tftp. when this pseudo-user exists, bootpd treats all absolute pathnames as being relative to this user’s home directory. In all cases, existence of a file means that, in addition to actually being present, the file must be readable by the pseudo-user tftp (or must be publicly readable, if no such pseudo-user exists) since this is also required by tftpd(1M) to permit the file transfer. All filenames are first tried as filename.hostname and then simply as filename, thus providing for individual per-host bootfiles.

bs=size
This tag specifies the size of the bootfile. The parameter size can 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. Specifying the bs symbol as a boolean has the same effect as specifying auto as its value.

cs=ip-address-list
This tag specifies the IP address(es) of RFC865 Quote of the Day (cookie) server(s).

ds=ip-address-list
This tag specifies the IP address(es) of RFC1034 Domain Name server(s).

gw=ip-address-list
This tag specifies the IP address(es) of gateway(s) for the client’s subnet. If one of many gateways is preferred, it should be listed first.

ha=hardware-address
This tag specifies the hardware address of the client. The hardware address must be specified in hexadecimal; optional periods and/or a leading 0x can be included for readability. The ha tag must be preceded by the ht tag (either explicitly or implicitly; see tc below).

hd=home-directory
This tag specifies a directory name to which the bootfile is appended (see bf tag above). The default value of the hd tag is /.

hn The presence of this tag indicates that the hostname should be sent in the boot reply. The hn tag is a boolean tag. bootpd attempts to send the entire hostname as it is specified in the configuration file; if this cannot fit into the reply packet, an attempt is made to shorten the name 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 can fit, nothing is sent.

ht=hardware-type
This tag specifies the hardware type code. The hardware-type parameter can be an unsigned decimal, octal, or hexadecimal integer corresponding to one of the ARP Hardware Type codes specified in RFC1010. It can also be specified by the symbolic names ethernet or ether for 10-Mb Ethernet; ethernet3 or ether3 for 3-Mb experimental Ethernet; ieee802, tr, or token-ring for IEEE 802 networks; pronet for Proteon ProNET Token Ring; chaos, arcnet, or ax.25 for Chaos, ARCNET, and AX.25 Amateur Radio networks, respectively.

im=ip-address-list
This tag specifies the IP address(es) of Impress network image server(s).

ip=ip-address
This tag specifies the IP address of the BOOTP client.

lg=ip-address-list
This tag specifies the IP address(es) of MIT-LCS UDP log server(s).

lp=ip-address-list
This tag specifies the IP address(es) of Berkeley 4BSD printer server(s).

ns=ip-address-list
This tag specifies the IP address(es) of IEN-116 name server(s).

rl=ip-address-list
This tag specifies the IP address(es) of RFC887 Resource Location Protocol server(s).

sm=subnet-mask
This tag specifies the client’s subnet mask. The subnet-mask is specified as a single IP address.

Tnnn=generic-data
This is a generic tag where nnn is an RFC1048 vendor field tag number. This allows bootpd to immediately take advantage of future extensions to RFC1048. The generic-data data can 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 RFC1048-style boot reply.

tc=template-host
This tag indicates a table continuation. Often, many host entries share common values for certain tags (such as domain 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 mechanism.

The template-host is a dummy host that does not actually exist and never sends boot requests. 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 template-host can 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 FItag@ which removes the effect of tag. For example, to completely undo an RFC1034 domain name server specification, use :ds@: at an appropriate place in the configuration entry. After removal with @, a tag is eligible to be set again through the tc mechanism.

to=offset
This tag specifies the client’s time zone offset in seconds from UTC. The time offset may be either a signed decimal integer 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.

ts=ip-address-list
This tag specifies the IP address(es) of RFC868 Time Protocol server(s).

vm=magic-cookie
This tag specifies the RFC1048 vendor information magic cookie. The magic-cookie may be one of the following keywords: auto (indicating that vendor information is determined by the client’s request), rfc1048 (which always forces an RFC1048-style reply), or cmu (which always forces a CMU-style reply).

EXAMPLE

An example /etc/bootptab file follows:

# The first entry is the template for options
# common to all the X terminals.
global.defaults:\
:bf=C2300A:\
:hd=/usr/lib/X11/700X/bin:\
:hn:\
:ht=ether:\
:vm=rfc1048:
# Now the actual entries for the individual
# X terminals are listed.
xterm1:\
:tc=global.defaults:\
:ha=08000903212F:\
:ip=190.40.101.22:
xterm2:\
:tc=global.defaults:\
:ha=0800090324AC:\
:ip=190.40.101.35:

FILES

/etc/bootptab
/etc/services

WARNINGS

Individual host entries must not exceed 1024 characters.

AUTHOR

bootpd was developed by Carnegie Mellon University and Stanford University.

Museum

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