shadowsocks-libev/libudns/dnsget.1

.\" dnsget.1: dnsget manpage
.\"
.\" Copyright (C) 2005-2014  Michael Tokarev <mjt+udns@tls.msk.ru>
.\" This file is part of UDNS library, an async DNS stub resolver.
.\"
.\" This library is free software; you can redistribute it and/or
.\" modify it under the terms of the GNU Lesser General Public
.\" License as published by the Free Software Foundation; either
.\" version 2.1 of the License, or (at your option) any later version.
.\"
.\" This library is distributed in the hope that it will be useful,
.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
.\" Lesser General Public License for more details.
.\"
.\" You should have received a copy of the GNU Lesser General Public
.\" License along with this library, in file named COPYING.LGPL; if not,
.\" write to the Free Software Foundation, Inc., 59 Temple Place,
.\" Suite 330, Boston, MA  02111-1307  USA

.TH dnsget 1 "Jan 2014" "User Utilities"

.SH NAME
dnsget \- DNS lookup utility

.SH SYNOPSYS
.B dnsget
.RB [\| \-v \||\| \-q \|]
.RB [\| \-c
.IR class \|]
.RB [\| \-t
.IR type \|]
.RB [\| \-o
.IR opt , opt ,...]
.IR name \|.\|.\|.

.SH DESCRIPTION
.B dnsget
is a simple command-line to perform DNS lookups, similar to
.BR host (1)
and
.BR dig (1).
It is useable for both interactive/debugging scenarious and
in scripts.
The program is implemented using
.BR udns (3)
library.

.PP
By default,
.B dnsget
produces a human-readable output, similar to
.RS
.nf
alias.example.com. CNAME www.example.com.
www.example.com. A 192.168.1.1
www.example.com. MX 10 mx.example.com.
.fi
.RE
which is just sufficient to see how a given name resolves.
Output format is controllable with
.B \-v
and
.B \-q
options -- the former increases verbosity level up to printing
the whole DNS contents of all packets sent and received, which
is suitable for debugging DNS problems, while the latter reduces
the level, making output more quiet, up to bare result with no
error messages, which is good for scripts.

.SH OPTIONS

The following options are recognized by
.BR dnsget :

.TP
.B \-v
produce more detailed output.  More
.BR \-v 's
means more details will be produced.  With single
.BR \-v , dnsget
will print contents of all received DNS packets (in a readable format),
while with
.BR \-vv ,
it will output all outgoing DNS packets too.

.TP
.B \-q
the opposite for \fB\-v\fR -- produce less detailed output.
With single
.BR \-q , dnsget
will only show (decoded) data from final DNS resource records (RR),
while
.B \-qq
also suppresses error messages.

.TP
\fB\-t \fItype\fR
request record(s) of the given type \fItype\fR.  By default,
.B dnsget
will ask for IPv4 address (A) record, or for PTR record if the
argument in question is an IPv4 or IPv6 address.  Recognized
types include A, AAAA, MX, TXT, CNAME, PTR, NS, SOA, ANY and
others.

.TP
\fB\-c \fIclass\fR
request DNS record(s) of the given class \fIclass\fR.  By
default
.B dnsget
uses IN class.  Valid classes include IN, CH, HS, ANY.

.TP
.B \-a
(compatibility option).  Equivalent to setting query type to
.B ANY
and increasing verbosity level
.RB ( \-v ).

.TP
.B \-C
(planned)

.TP
.B \-x
(planned)

.TP
\fB\-o \fIopt\fR,\fIopt\fR,...
(may be specified several times).
Set resolver options (in a form \fIoption\fR:\fIvalue\fR) as if they
were set in
.RB $ RES_OPTIONS
environment variable, or set query flags:
.RS
.TP
\fBtimeout\fR:\fIsec\fR
Set initial query timeout to \fIsec\fR.
.TP
\fBattempts\fR:\fInum\fR
(re)try every query \fInum\fR times before failing.
.TP
\fBudpbuf\fR:\fIbytes\fR
set DNS UDP buffer size to \fIbytes\fR bytes.  Valid values
are from 512 to 65535.  If \fIbytes\fR is greather than 512,
EDNS0 (RFC 2671) extensions will be used.
.TP
\fBport\fR:\fInum\fR
Use given UDP port number \fInum\fR instead of the default port 53 (domain).
.TP
\fBaa\fR
set AA (auth only) query bit.
.TP
\fBnord\fR
do not set RD (recursion desired) query bit (set by default).
.TP
\fBdnssec\fR or \fBdo\fR
set DNSSEC OK (DO) query flag (\fBdnsget\fR does not verify DNSSEC signatures,
only displays them; this is set in EDNS RR).
.TP
\fBcd\fR
set CD (checking disabled) query bit.
.RE

.TP
\fB\-n \fInameserver\fR
Use the given nameserver(s) (may be specified more than once)
instead of the default.  Using this option has the same same effect as 
.RB $ NSCACHEIP
or
.RB $ NAMESERVERS
environment variables, with the only difference that only IPv4 addresses
are recognized for now, and it is possible to specify names (which will
be resolved using default settings) instead of IP addresses.

.TP
.B \-h
print short help and exit.

.SH "RETURN VALUE"
When all names where resovled successefully,
.B dnsget
exits with zero exit status.  If at least one name was not found,
.B dnsget
will exit with return code 100.  If some other error occured during
name resolution, it will exit with code 99.  In case of usage or
initialization error,
.B dnsget
will return 1.

.SH "SEE ALSO"
.BR host (1)
.BR dig (1)
.BR resolv.conf (5)
.BR udns (3).