dig.1

早期freebsd实现

.\" $Id: dig.1,v 4.9.1.2 1993/09/08 00:00:49 vixie Exp $
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.\" --Copyright--
.\"
.\" Distributed with 'dig' version 2.0 from University of Southern
.\" California Information Sciences Institute (USC-ISI).
.\"
.\"       dig.1   2.0 (USC-ISI) 8/30/90
.\"
.\" Man page reformatted for this release by Andrew Cherenson
.\" ([e-mail])
.\"
.TH DIG 1 "August 30, 1990"
.SH NAME
dig \- send domain name query packets to name servers
.SH SYNOPSIS
.B dig 
.RI [ @\fIserver\fP ]
.I domain
.RI [ "<query-type>" ]
.RI [ "<query-class>" ]
.RI [ "+<query-option>" ]
.RI [ "\-<dig-option>" ]
.RI [ "%comment" ]
.SH DESCRIPTION
\fIDig\fP (domain information groper) is a flexible command line tool
which can be used to gather information from the Domain
Name System servers. \fIDig\fP has two modes: simple interactive mode
which makes a single query, and batch which executes a query for
each in a list of several query lines. All query options are
accessible from the command line.
.PP
The usual simple use of \fIdig\fP will take the form:
.sp 1
	dig  @server  domain   query-type  query-class
.sp 1
where:
.IP \fIserver\fP 
may be either a domain name or a dot-notation
Internet address. If this optional field is omitted, \fIdig\fP
will attempt to use the default name server for your machine.
.sp 1
\fBNote:\fP If a domain name is specified, this will be resolved
using the domain name system resolver (i.e., BIND). If your
system does not support DNS,  you may \fIhave\fP to specify a
dot-notation address.  Alternatively, if there is a server
at your disposal somewhere,  all that is required is that
/etc/resolv.conf be present and indicate where the default
name servers  reside,  so that  \fIserver\fP itself can be
resolved. See 
.IR resolver (5)
for information on /etc/resolv.conf.
(WARNING: Changing /etc/resolv.conf will affect
the standard  resolver library and  potentially several
programs which use it.) As an option, the user may set the
environment variable LOCALRES to name a file which is to
be used instead of /etc/resolv.conf (LOCALRES is specific
to the \fIdig\fP resolver and  not referenced by the standard
resolver). If the LOCALRES variable is not set or the file
is not readable then /etc/resolv.conf will be used.
.IP \fIdomain\fP
is the domain name for which you are requesting information.
See OPTIONS [-x] for convenient way to specify inverse address
query.
.IP \fIquery-type\fP 
is the type of information (DNS query type) that
you are requesting. If omitted, the default is "a" (T_A = address).
The following types are recognized:
.sp 1
.ta \w'hinfoXX'u +\w'T_HINFOXX'u
.nf
a	T_A	network address
any	T_ANY	all/any information about specified domain
mx	T_MX	mail exchanger for the domain
ns	T_NS	name servers
soa	T_SOA	zone of authority record
hinfo	T_HINFO	host information
axfr	T_AXFR	zone transfer
		 (must ask an authoritative server)
txt	T_TXT	arbitrary number of strings
.fi
.sp 1
(See RFC 1035 for the complete list.)
.IP \fIquery-class\fP
is the network class requested in the query. If
omitted, the default is "in" (C_IN = Internet).
The following classes are recognized:
.sp 1
.ta \w'hinfoXX'u +\w'T_HINFOXX'u
.nf
in	C_IN	Internet class domain
any	C_ANY	all/any class information
.fi
.sp 1
(See RFC 1035 for the complete list.)
.sp 1
\fBNote:\fP
"Any" can be used to specify a class and/or a type of
query. \fIDig\fP will parse the first occurrence of "any"
to mean query-type = T_ANY. To specify query-class =
C_ANY you must either specify "any" twice, or set
query-class using "\-c" option (see below).
.SH OTHER OPTIONS
.IP "%ignored-comment"
"%" is used to included an argument that is simply not
parsed.  This may be useful  if running \fIdig\fP in batch
mode. Instead of resolving every @server-domain-name in
a list of queries, you can avoid the overhead of doing
so, and still have the domain name on the command line
as a reference. Example:
.sp 1
	dig  @128.9.0.32  %venera.isi.edu  mx  isi.edu
.sp 1
.IP "\-<dig option>"
"\-" is used to specify an option which effects the
operation of \fIdig\fP. The following options are currently
available (although not guaranteed to be useful):
.RS
.IP "\-x \fIdot-notation-address\fP"
Convenient form to specify inverse address mapping.
Instead of "dig 32.0.9.128.in-addr.arpa" one can
simply "dig -x 128.9.0.32".
.IP "\-f \fIfile\fP"
File for \fIdig\fP batch mode. The file contains a list
of query specifications (\fIdig\fP command lines) which
are to be executed successively. Lines beginning
with ';', '#', or '\\n' are ignored. Other options
may still appear on command line, and will be in
effect for each batch query.
.IP "\-T \fItime\fP"
Time in seconds between start of successive
queries when running in batch mode. Can be used
to keep two or more batch \fIdig\fP commands running
roughly in sync. Default is zero.
.IP "\-p \fIport\fP"  
Port number. Query a name server listening to a
non-standard port number. Default is 53.
.IP "\-P[\fIping-string\fP]"
After query returns, execute a 
.IR ping (8)
command
for response time comparison. This rather
unelegantly makes a call to the shell. The last
three lines of statistics is printed for the
command:
.sp 1
	ping \-s server_name 56 3
.sp 1
If the optional "ping string" is present, it
replaces "ping \-s" in the shell command.
.IP "\-t \fIquery-type\fP"
Specify type of query. May specify either an
integer value to be included in the type field
or use the abbreviated mnemonic as discussed
above (i.e., mx  = T_MX).
.IP "\-c \fIquery-class\fP"  
Specify class of query. May specify either an
integer value to be included in the class field
or use the abbreviated mnemonic as discussed
above (i.e., in = C_IN).
.IP "\-envsav"
This flag specifies that the \fIdig\fP environment
(defaults, print options, etc.), after
all of the arguments are parsed, should be saved
to a file to become the default environment.
Useful if you do not like the standard set of
defaults and do not desire to include a
large number of options each time \fIdig\fP is used.
The environment consists of resolver state
variable flags, timeout, and retries as well as
the flags detailing \fIdig\fP output (see below).
If the shell environment variable LOCALDEF is set
to the name of a file, this is where the default
\fIdig\fP environment is saved. If not, the file
"DiG.env" is created in the current working directory.
.sp 1
\fBNote:\fP LOCALDEF is specific to the \fIdig\fP resolver,
and will not affect operation of the standard
resolver library.
.sp 1
Each time \fIdig\fP is executed, it looks for "./DiG.env"
or the file specified by the shell environment variable
LOCALDEF. If such file exists and is readable, then the
environment is restored from this file
before any arguments are parsed.
.IP "\-envset"
This flag only affects
batch query runs. When "\-envset" is
specified on a line in a \fIdig\fP batch file,
the \fIdig\fP environment after the arguments are parsed,
becomes the default environment for the duration of
the batch file, or until the next line which specifies
"\-envset".
.IP "\-[no]stick"
This flag only affects batch query runs.
It specifies that the \fIdig\fP environment (as read initially
or set by "\-envset" switch) is to be restored before each query
(line) in a \fIdig\fP batch file.
The default "\-nostick" means that the \fIdig\fP environment
does not stick, hence options specified on a single line
in a \fIdig\fP batch file will remain in effect for
subsequent lines (i.e. they are not restored to the
"sticky" default).

.RE
.IP "+<query option>"
"+" is used to specify an option to be changed in the
query packet or to change \fIdig\fP output specifics. Many
of these are the same parameters accepted by 
.IR nslookup (1).
If an option requires a parameter, the form is as
follows:
.sp 1
	+keyword[=value]
.sp 1
Most keywords can be abbreviated.  Parsing of the "+"
options  is very  simplistic \(em a value must not be
separated from its keyword by white space. The following
keywords are currently available:
.sp 1
.nf
.ta \w'domain=NAMEXX'u +\w'(deb)XXX'u
Keyword	Abbrev.	Meaning [default]

[no]debug	(deb)	turn on/off debugging mode [deb]
[no]d2		turn on/off extra debugging mode [nod2]
[no]recurse	(rec)	use/don't use recursive lookup [rec]
retry=#	(ret)	set number of retries to # [4]
time=#	(ti)	set timeout length to # seconds [4]
[no]ko		keep open option (implies vc) [noko]
[no]vc		use/don't use virtual circuit [novc]
[no]defname	(def)	use/don't use default domain name [def]
[no]search	(sea)	use/don't use domain search list [sea]
domain=NAME	(do)	set default domain name to NAME
[no]ignore	(i)	ignore/don't ignore trunc. errors [noi]
[no]primary	(pr)	 use/don't use primary server [nopr]
[no]aaonly	(aa)	authoritative query only flag [noaa]
[no]sort	(sor)	sort resource records [nosor]
[no]cmd		echo parsed arguments [cmd]
[no]stats	(st)	print query statistics [st]
[no]Header	(H)	print basic header [H]
[no]header	(he)	print header flags [he]
[no]ttlid	(tt)	print TTLs [tt]
[no]cl			print class info [nocl]
[no]qr		print outgoing query [noqr]
[no]reply	(rep)	print reply [rep]
[no]ques	(qu)	print question section [qu]
[no]answer	(an)	print answer section [an]
[no]author	(au)	print authoritative section [au]
[no]addit	(ad)	print additional section [ad]
pfdef		set to default print flags
pfmin		set to minimal default print flags
pfset=#		set print flags to #
		(# can be hex/octal/decimal)
pfand=#		bitwise and print flags with #
pfor=#		bitwise or print flags with #
.fi
.sp 1
The retry and time options affect the retransmission strategy used by resolver 
library when sending datagram queries. The algorithm is as follows:
.sp 1
.in +5n
.nf
for i = 0 to retry \- 1
    for j = 1 to num_servers
	send_query
	wait((time * (2**i)) / num_servers)
    end
end
.fi
.in -5n
.sp 1
(Note: \fIdig\fP always uses a value of 1 for num_servers.) 
.SH DETAILS
\fIDig\fP once required a slightly modified version of the BIND 
.IR resolver (3)
library.  BIND's resolver has (as of BIND 4.9) been augmented to work
properly with \fIDig\fP.  Essentially, \fIDig\fP is a straight-forward
(albeit not pretty) effort of parsing arguments and setting appropriate
parameters.  \fIDig\fP uses resolver routines res_init(), res_mkquery(),
res_send() as well as accessing _res structure. 
.SH FILES
.ta \w'/etc/resolv.confXX'u
/etc/resolv.conf	initial domain name and name server 
\./DiG.env		default save file for default options
.br
	addresses
.SH ENVIRONMENT
LOCALRES	file to use in place of /etc/resolv.conf
.br
LOCALDEF	default environment file
.SH AUTHOR
Steve Hotz 
[e-mail]
.SH ACKNOWLEDGMENTS
\fIDig\fP uses functions from 
.IR nslookup (1)
authored by Andrew Cherenson.
.SH BUGS
\fIDig\fP has a serious case of "creeping featurism" -- the result of
considering several potential uses during it's development.  It would
probably benefit from a rigorous diet.  Similarly, the print flags
and granularity of the items they specify make evident their
rather ad hoc genesis.
.PP
\fIDig\fP does not consistently exit nicely (with appropriate status)
when a problem occurs somewhere in the resolver (NOTE: most of the common
exit cases are handled).  This is particularly annoying when running in
batch mode.  If it exits abnormally (and is not caught), the entire
batch aborts; when such an event is trapped, \fIdig\fP simply
continues with the next query.
.SH SEE ALSO
named(8),  resolver(3),  resolver(5),  nslookup(1)