bootptab(4) CLIX bootptab(4)
NAME
bootptab - Configuration file for bootpd
DESCRIPTION
The /etc/bootptab configuration file has a format similar to that of
termcap in which two-character case-sensitive tag symbols are used to
represent host parameters. These parameter declarations are separated by
colons (:). The general format is:
hostname:tg=value. . . :tg=value. . . :tg=value. . . .
The hostname parameter 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 may also appear in a boolean form with no
value (i.e. :tg:). The currently recognized tags are as follows:
bc Use broadcast address in reply.
bf Bootfile.
bs Bootfile size in 512-octet blocks.
cs Cookie server address list.
ds Domain name server address list.
gw Gateway address list.
ha Host hardware address.
hd Bootfile home directory.
hn Send hostname.
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.
rl Resource location protocol server address list.
sm Host subnet mask.
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bootptab(4) CLIX bootptab(4)
tc Table continuation (points to similar "template" host entry).
to Time offset in seconds from UTC.
ts Time server address list.
vm Vendor magic cookie selector. There is also a generic tag, Tn, where
n is an RFC1048 vendor field tag number. Thus it is possible to
immediately take advantage of future extensions to RFC1048 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 RFC1048-style
bootp reply.
The following tags accept a space-separated list of IP addresses: cs, ds,
gw, im, lg, lp, ns, rl, and ts. The ip and sm 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').
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 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).
The bc boolean tag indicates that replies sent to a requestor that doesn't
yet have an internet address configured should be sent via the broadcast
address.
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 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
prepending the value of the hd tag and testing for existence of the file.
If the hd tag is not supplied in the configuration file or if the
resulting boot file cannot be found, then the request is discarded.
Clients which specify null boot files will always elicit a reply from the
server. The exact reply will again depend upon the hd and bf tags. If
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bootptab(4) CLIX bootptab(4)
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.
In all these cases, existence of the file means that, in addition to
actually being present, the file must have its public read access bit set,
since this is required by tftpd to permit the file transfer. Also, all
filenames are first tried as filename.hostname and then simply as
filename, thus providing for individual per-host bootfiles.
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 (which always forces an RFC1048-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 RFC1048 clients. The bootpd server 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 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
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bootptab(4) CLIX bootptab(4)
inferred via tc. This can be done using the construction tag @ which
removes the effect of tag as in termcap. For example, to completely undo
an IEN-116 name server specification, use :ns@: at an appropriate place in
the configuration entry. After removal @, a tag is eligible to be set
again through the tc mechanism.
Blank lines and lines beginning with a number sign (#) 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.
EXAMPLES
The following is an example of a /etc/bootptab file:
# Sample bootptab file
default1:\
:hd=/usr/boot:bf=null:\
:ds=128.2.35.50 128.2.13.21:\
:ns=0x80020b4d 0x80020ffd:\
:ts=0x80020b4d 0x80020ffd:\
:sm=255.255.0.0:gw=0x8002fe24:\
:hn:vm=auto:to=-18000:\
:T37=0x12345927AD3BCF:T99="Special ASCII string":
carnegie:ht=6:ha=7FF8100000AF:ip=128.2.11.1:tc=default1:
baldwin:ht=1:ha=0800200159C3:ip=128.2.11.10:tc=default1:
wylie:ht=1:ha=00DD00CADF00:ip=128.2.11.100:tc=default1:
arnold:ht=1:ha=0800200102AD:ip=128.2.11.102:tc=default1:
bairdford:ht=1:ha=08002B02A2F9:ip=128.2.11.103:tc=default1:
bakerstown:ht=1:ha=08002B0287C8:ip=128.2.11.104:tc=default1:
# Special domain name server for next host
butlerjct:ht=1:ha=08002001560D:ip=128.2.11.108:ds=128.2.13.42:tc=default1:
gastonville:ht=6:ha=7FFF81000A47:ip=128.2.11.115:tc=default1:
hahntown:ht=6:ha=7FFF81000434:ip=128.2.11.117:tc=default1:
hickman:ht=6:ha=7FFF810001BA:ip=128.2.11.118:tc=default1:
lowber:ht=1:ha=00DD00CAF000:ip=128.2.11.121:tc=default1:
mtoliver:ht=1:ha=00DD00FE1600:ip=128.2.11.122:tc=default1:
RELATED INFORMATION
Commands: bootpd(8)
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