.\"	$OpenBSD: dig.1,v 1.12 1999/06/05 01:29:39 aaron Exp $
.\" $From: dig.1,v 8.2 1997/06/01 20:34:33 vixie Exp $
.\"
.\" ++Copyright++ 1993
.\" -
.\" Copyright (c) 1993
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" Portions Copyright (c) 1993 by Digital Equipment Corporation.
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies, and that
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.\" WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
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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
.\" (arc@sgi.com)
.\"
.Dd August 30, 1990
.Os
.Dt dig 1
.Sh NAME
.Nm dig
.Nd send domain name query packets to name servers
.Sh SYNOPSIS
.Nm dig
.Op Cm @ Ns Ar server
.Ar domain
.Op Ar query-type
.Op Ar query-class
.\" .Op Cm \&- Ns Ar dig-option
.Op Fl f Ar file
.Op Fl T Ar time
.Op Fl p Ar port
.Op Fl P Ns Op Ar ping-string
.Op Fl t Ar query-type
.Op Fl c Ar query-class
.Op Fl envsav
.Op Fl envset
.Op Fl stick | Fl nostick
.Oo
.Cm + Ns Ar keyword Ns 
.Oo
.Cm \= Ns Ar value
.Oc
.Oc
.Op Cm % Ns Ar comment
.Nm dig
.Op Cm @ Ns Ar server
.Fl x Ar dot-notation-address
.Op ...
.Sh DESCRIPTION
.Nm
(domain information groper) is a flexible command line tool
which can be used to gather information from the Domain
Name System servers.
.Nm
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
.Nm
will take the form:
.Bd -filled -offset indent 
.Ic dig 
.Cm @ Ns Ar server 
.Ar domain 
.Ar query-type 
.Ar query-class
.Ed
where:
.Bl -tag -width "query-class" -offset
.It Ar server
may be either a domain name or a dot-notation
Internet address. If this optional field is omitted,
.Nm
will attempt to use the default name server for your machine.
.Pp
.Sy Note:
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
.Em have
to specify a
dot-notation address. Alternatively, if there is a server
at your disposal somewhere, all that is required is that
.Pa /etc/resolv.conf
be present and indicate where the default
name servers reside, so that 
.Ar server
itself can be
resolved. See
.Xr resolv.conf 5
for information on
.Pa /etc/resolv.conf .
.Pp
.Sy Warning:
Changing
.Pa /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
.Ev LOCALRES
to name a file which is to
be used instead of
.Pa /etc/resolv.conf
.Ev ( LOCALRES
is specific
to the
.Nm
resolver and not referenced by the standard
resolver). If the
.Ev LOCALRES
variable is not set or the file
is not readable then
.Pa /etc/resolv.conf
will be used.
.It Ar domain
is the domain name for which you are requesting information.
See
.Sx "OTHER OPTIONS"
.Fl ( x )
for a convenient way to specify inverse address
query.
.It Ar query-type
is the type of information (DNS query type) that
you are requesting. If omitted, the default is
.Dq Li 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.)
.It Ar query-class
is the network class requested in the query. If
omitted, the default is
.Dq Li 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
.Sy Note:
.Dq Li any
can be used to specify a class and/or a type of
query.
.Nm
will parse the first occurrence of
.Dq Li any
to mean
.Ar query-type
= T_ANY. To specify
.Ar query-class
= C_ANY you must either specify
.Dq Li any
twice, or set
query-class using
.Fl c
option (see below).
.El
.Sh OTHER OPTIONS
.Bl -tag -width Ar -offset
.It Cm % Ns ignored-comment
.Dq Li %
is used to included an argument that is simply not
parsed. This may be useful if running
.Nm
in batch
mode. Instead of resolving every 
.Cm @ Ns Ar 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:
.D1 Ic "dig @128.9.0.32 %venera.isi.edu mx isi.edu"
.\" .It Cm \- Ns dig-option
.\" .Dq Li \-
.\" is used to specify an option which affects the
.\" operation of
.\" .Nm dig .
.\" The following options are currently
.\" available (although not guaranteed to be useful):
.\" .Bl -tag -width Fl -offset
.It Fl x Ar dot-notation-address
Convenient form to specify inverse address mapping.
Instead of
.D1 Ic "dig 32.0.9.128.in-addr.arpa"
one can
simply
.D1 Ic "dig -x 128.9.0.32"
.It Fl f Ar file
File for
.Nm
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.
.It Fl T Ar time
Time in seconds between start of successive
queries when running in batch mode. Can be used
to keep two or more batch
.Nm
commands running
roughly in sync. Default is zero.
.It Fl p Ar port
Port number. Query a name server listening to a
non-standard port number. Default is 53.
.It Fl P Ns Op Ar ping-string
After query returns, execute a
.Xr ping 1
command
for response time comparison. This rather
inelegantly makes a call to the shell. The last
three lines of statistics are printed for the
command:
.Dl ping -s server_name 56 3
If the optional
.Ar ping-string
is present, it
replaces
.Dq Li "ping \-s"
in the shell command.
.It Fl t Ar query-type
Specify the type of query. This 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).
.It Fl c Ar query-class
Specify the class of query. This 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).
.It Fl envsav
This flag specifies that the
.Nm
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
.Nm
is used.
The environment consists of resolver state
variable flags, timeout, and retries as well as
the flags detailing
.Nm
output (see below).
If the shell environment variable
.Ev LOCALDEF
is set
to the name of a file, this is where the default
.Nm
environment is saved. If not, the file
.Pa DiG.env
is created in the current working directory.
.sp 1
.Sy Note:
.Ev LOCALDEF
is specific to the
.Nm
resolver,
and will not affect operation of the standard
resolver library.
.sp 1
Each time
.Nm
is executed, it looks for
.Pa DiG.env
int the working directory,
or the file specified by the shell environment variable
.Ev LOCALDEF .
If the file exists and is readable, then the
environment is restored from it
before any arguments are parsed.
.It Fl envset
This flag only affects
batch query runs. When
.Fl envset
is
specified on a line in a
.Nm
batch file, the
.Nm
environment after the arguments are parsed,
becomes the default environment for the duration of
the batch file, or until the next line which specifies
.Fl envset .
.It Fl stick | Fl nostick
These flags only affects batch query runs.
.Fl stick
specifies that the
.Nm
environment (as read initially
or set by
.Fl envset
switch) is to be restored before each query
(line) in a
.Nm
batch file.
The default
.Fl nostick
means that the
.Nm
environment
does not stick; that is, options specified on a single line
in a
.Nm
batch file will remain in effect for
subsequent lines (i.e. they are not restored to the
.Dq sticky
default).
.\" .El
.It Xo Cm + Ns Ar keyword Ns 
.Op = Ns Ar value
.Xc
.Dq Li "+"
is used to specify an option to be changed in the
query packet or to change
.Nm
output specifics. Many
of these are the same parameters accepted by
.Xr nslookup 8 .
.\" If an option requires a parameter, the form is as
.\" follows:
.\" .Bd -ragged -offset indent 
.\" .Cm + Ns Ar keyword Ns 
.\" .Oo
.\" .Cm \= Ns Ar value
.\" .Oc
.\" .Ed
.Pp
Most keywords can be abbreviated. Parsing of the
.Dq Li "+"
options is very simplistic \(em a value must not be
separated from its keyword by white space. The following
.Ar keyword Ns
s 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 
.Ar retry
and 
.Ar time
keywords affect the retransmission strategy used by resolver
library when sending datagram queries. The algorithm is as follows:
.Bd -literal -offset indent
for i = 0 to retry \- 1
    for j = 1 to num_servers
	send_query
	wait((time * (2**i)) / num_servers)
    end
end
.Ed
.Pp
.Sy Note:
.Nm
always uses a value of 1 for
.Va num_servers .
.El
.Sh DETAILS
.Nm
once required a slightly modified version of the BIND
.Xr resolver 3
library. BIND's resolver has (as of BIND 4.9) been augmented to work
properly with
.Nm dig .
Essentially,
.Nm
is a straight-forward
(albeit not pretty) effort of parsing arguments and setting appropriate
parameters.
.Nm
uses resolver routines
.Fn res_init ,
.Fn res_mkquery ,
.Fn res_send
as well as accessing the
.Va _res
structure.
.Sh FILES
.Bl -tag -width Pa -compact -offset indent
.It Pa /etc/resolv.conf
initial domain name and name server addresses
.It Pa DiG.env		
default save file for default options
.El
.Sh ENVIRONMENT
.Bl -tag -width Ev -compact -offset indent
.It Ev LOCALRES
file to use in place of
.Pa /etc/resolv.conf
.It Ev LOCALDEF
default environment file
.El
.Sh AUTHOR
Steve Hotz
hotz@isi.edu
.Sh ACKNOWLEDGMENTS
.Nm
uses functions from
.Xr nslookup 8
authored by Andrew Cherenson.
.Sh BUGS
.Nm
has a serious case of
.Dq creeping featurism
\(em 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
.Nm
does not consistently exit nicely (with appropriate status)
when a problem occurs somewhere in the resolver.
.Sy ( Note:
most of the common
exit cases are handled). This is particularly annoying when running in
batch mode. If the resolver exits abnormally (and is not caught), the entire
batch aborts; when such an event is trapped,
.Nm
simply continues with the next query.
.Sh SEE ALSO
.Xr resolver 3 ,
.Xr resolv.conf 5 ,
.Xr named 8 ,
.Xr nslookup 8