[adns] / README.html

<html><head><title>adns - advanced, alternative, asynchronous resolver</title>
<link rev="made" href="mailto:adns-maint@chiark.greenend.org.uk">
<meta name="keywords" content="adns">
</head>
<body>
<h1>GNU adns</h1>

<strong>Advanced, easy to use, asynchronous-capable DNS client
library and utilities.</strong>

<!--      Note: this file must contain portable HTML !            -->
<!--                                                              -->
<!--  It is served on the GNU site and also from my own system,   -->
<!--  under the URL http://www.chiark.greenend.org.uk/adns/       -->
<!--  Please ensure that all links continine to be correct        -->
<!--  both for www.gnu.org and chiark.                            -->
<!--                                                              -->

<p>

adns is a resolver library for C (and C++) programs, and a collection
of useful DNS resolver utilities.


<h2>C library</h2>

In contrast with the standard interfaces, gethostbyname et al and
libresolv, it has the following features:

<ul>

<li>It is reasonably easy to use for simple programs which just want
to translate names to addresses, look up MX records, etc.

<li>It can be used in an asynchronous, non-blocking, manner.  Many
queries can be handled simultaneously.

<li>Responses are decoded automatically into a natural representation
for a C program - there is no need to deal with DNS packet and RRDATA
formats.

<li>Sanity checking (eg, name syntax checking, reverse/forward
correspondence, CNAME pointing to CNAME) is performed automatically
by default.

<li>Time-to-live, CNAME and other similar information is returned in
an easy-to-use form, without getting in the way.

<li>There is no global state in the library; resolver state is an
opaque data structure which the client creates explicitly.  A program
can have several instances of the resolver.

<li>Errors are reported to the application in a way that distinguishes
the various causes of failure properly.

<li>adns understands conventional resolv.conf, but this can overridden
by environment variables.

<li>Flexibility.  For example, the application can tell adns to:
ignore environment variables (for setuid programs), disable hostname
syntax sanity checks to return arbitrary data, override or ignore
resolv.conf in favour of supplied configuration, etc.

<li>Believed to be correct !  For example, will correctly back off to
TCP in case of long replies or queries, or to other nameservers if
several are available.  It has sensible handling of bad responses etc.

</ul>

<h2>DNS utility programs</h2>

adns also comes with a number of utility programs for use from the
command line and in scripts:

<ul>

<li><code>adnslogres</code> is a much faster version of Apache's
logresolv program.

<li><code>adnsresfilter</code> is a filter which copies its input to
its output, replacing IP addresses by the corresponding names, without
unduly delaying the output.  For example, you can usefully pipe the
output of netstat -n, tcpdump -ln, and the like, into it.

<li><code>adnshost</code> is a general-purpose DNS lookup utility
which can be used easily in from the command line and from shell
scripts to do simple lookups.  In a more advanced mode it can be used
as a general-purpose DNS helper program for scripting languages which
can invoke and communicate with subprocesses.  See the
<A href="http://www.chiark.greenend.org.uk/~ian/adns/docs/adnshost.txt">adnshost
usage message</A> for a summary of its capabilities.

</ul>

<h2>Documentation</h2>

I'm afraid there is no manual yet.  However, competent C programmers
should be able to use the library based on the
<A href="http://www.chiark.greenend.org.uk/~ian/adns/docs/adns.h.txt">commented
adns.h header file</A>, and the usage messages for the programs should
be sufficient.

<h2>Feedback</h2>

I'd be pleased if you would let me know if you're using my library in
your project, and what you think of it.

<p>

Bug reports should be reported to the
<a href="http://debbugs.gnu.org/">GNU Debbugs</a>.  Send an email
to <code>submit@debbugs.gnu.org</code> and at the top of your email,
in a paragraph of its own, write the single line
<pre>
Package: adns
</pre>
Your bug report will be published via to the adns-discuss list.

<p>

Feedback and discussion takes place on the <code>adns-discuss</code>
list.  You can mail me privately
at <code>ijackson@chiark.greenend.org.uk</code>.

<h2>Mailinglists</h2>

I have set up mailinglists <code>adns-announce</code> and
<code>adns-discuss</code>.  The announcements list is moderated and
will contain only announcements of important bugs, new versions, etc.

<p>

There are
<A href="http://www.chiark.greenend.org.uk/mailman/listinfo">archives
and subscription web pages</A>, or you can subscribe by sending mail
containing the word `subscribe' to
<code>adns-announce-REQUEST@chiark.greenend.org.uk</code> or
<code>adns-discuss-REQUEST@chiark.greenend.org.uk</code>.

<h2>Documentation</h2>

<ul>
<li><A href="http://www.chiark.greenend.org.uk/~ian/adns/docs/adns.h.txt">adns.h
    API header file with documentation comments</A>
<li><A href="http://www.chiark.greenend.org.uk/~ian/adns/docs/adnshost.txt">usage
    message for adnshost</A>
</ul>

<h2>Download and source code</h2>

<ul>
<li>The <A href="http://www.chiark.greenend.org.uk/~ian/adns/adns.tar.gz">current
    release</A> as a gzipped tarfile.
<li><A href="http://www.chiark.greenend.org.uk/~ian/adns/ftp/">Previous
    versions</A> and other files (including OpenPGP signatures).
<li><A href="http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git/adns.git/">master
    git (version control) repository browser</a>.
</ul>

adns is also available from the
<A href="http://www.gnu.org/">GNU Project</A> FTP servers and their
<A href="http://www.gnu.org/order/ftp.html">mirrors</A>.

<h2>Installation note</h2>

adns requires a real nameserver like BIND running on the same system
or a nearby one, which must be willing to provide `recursive service'.
I.e., adns is a `stub resolver'.

<p>
adns requires that your real nameserver is on the same machine, or
connected via a secure network, so that an attacker cannot fake the
replies to adns's queries.

<h2>References and related projects</h2>

<ul>
<li><a href="http://code.google.com/p/adns-python">Python bindings</a>
   by Andy Dustman.
<!-- <li><a href="http://cryp.to/hsdns/">Haskell bindings</a>
   by Peter Simons. -->
<li><a href="http://www.lysator.liu.se/liboop/">liboop event loop library</a>
   has a built-in binding for adns.
<li><a href="http://adns.jgaa.com/">port to MS Visual Studio 6 C++</a>
   by Jarle Aase.
</ul>

<h2>Copyright and licensing</h2>

<kbd>adns</kbd> is Copyright 1997-2000,2003,2006,2014-2016 Ian Jackson,
Copyright 2014 Mark Wooding, Copyright 1999-2000,2003,2006 Tony Finch,
and Copyright (C) 1991 Massachusetts Institute of Technology.

<p>

<kbd>adns</kbd> is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or (at
your option) any later version.

<p>

This program and documentation is distributed in the hope that it will
be useful, but <em>without any warranty</em>; without even the implied
warranty of <em>merchantability</em> or <em>fitness for a particular
purpose</em>.  See the
<A href="http://www.chiark.greenend.org.uk/~ian/adns/docs/COPYING.txt">GNU
General Public License</A> for more details.

<p>

You should have received a copy of the GNU General Public License
along with <kbd>adns</kbd>, or one should be available above; if not,
write to the <A href="http://www.fsf.org/">Free Software Foundation</A>
or email <code>ijackson@chiark.greenend.org.uk</code>.

<p>

<hr>
Ian Jackson / <tt>ijackson@chiark.greenend.org.uk</tt>.
<p>

<A href="http://www.gnu.org/">GNU home page</A>;
<A href="http://www.chiark.greenend.org.uk/">chiark home page</A>;
<A href="/">site or mirror home page</A>
<p>

This web page is Copyright (C)1996-2005,2014-2016 Ian Jackson.  See the
<A href="http://www.chiark.greenend.org.uk/~ian/sw-www-copy.html">Copyright/acknowledgements</A>.

</body>
</html>
Commit	Line	Data
ea5ac657	1	<html><head><title>adns - advanced, alternative, asynchronous resolver</title>
630bf698	2	<link rev="made" href="mailto:adns-maint@chiark.greenend.org.uk">
3a68c787	3	<meta name="keywords" content="adns">
630bf698	4	</head>
	5	<body>
	6	<h1>GNU adns</h1>
	7
	8	<strong>Advanced, easy to use, asynchronous-capable DNS client
	9	library and utilities.</strong>
	10
ea5ac657	11	<!-- Note: this file must contain portable HTML ! -->
b6922f88	12	<!-- -->
	13	<!-- It is served on the GNU site and also from my own system, -->
	14	<!-- under the URL http://www.chiark.greenend.org.uk/adns/ -->
	15	<!-- Please ensure that all links continine to be correct -->
	16	<!-- both for www.gnu.org and chiark. -->
	17	<!-- -->
b6922f88	18
630bf698	19	<p>
630bf698	20
8e5a4960	21	adns is a resolver library for C (and C++) programs, and a collection
b6922f88	22	of useful DNS resolver utilities.
	23
	24
	25	<h2>C library</h2>
	26
	27	In contrast with the standard interfaces, gethostbyname et al and
	28	libresolv, it has the following features:
630bf698	29
	30	<ul>
	31
	32	<li>It is reasonably easy to use for simple programs which just want
	33	to translate names to addresses, look up MX records, etc.
	34
	35	<li>It can be used in an asynchronous, non-blocking, manner. Many
	36	queries can be handled simultaneously.
	37
	38	<li>Responses are decoded automatically into a natural representation
2a9e6abd IJ	39	for a C program - there is no need to deal with DNS packet and RRDATA
2a9e6abd IJ	40	formats.
630bf698	41
630bf698	42	<li>Sanity checking (eg, name syntax checking, reverse/forward
2a9e6abd IJ	43	correspondence, CNAME pointing to CNAME) is performed automatically
2a9e6abd IJ	44	by default.
630bf698	45
	46	<li>Time-to-live, CNAME and other similar information is returned in
	47	an easy-to-use form, without getting in the way.
	48
	49	<li>There is no global state in the library; resolver state is an
	50	opaque data structure which the client creates explicitly. A program
	51	can have several instances of the resolver.
	52
	53	<li>Errors are reported to the application in a way that distinguishes
	54	the various causes of failure properly.
	55
2a9e6abd IJ	56	<li>adns understands conventional resolv.conf, but this can overridden
2a9e6abd IJ	57	by environment variables.
630bf698	58
630bf698	59	<li>Flexibility. For example, the application can tell adns to:
8e5a4960	60	ignore environment variables (for setuid programs), disable hostname
	61	syntax sanity checks to return arbitrary data, override or ignore
	62	resolv.conf in favour of supplied configuration, etc.
630bf698	63
	64	<li>Believed to be correct ! For example, will correctly back off to
	65	TCP in case of long replies or queries, or to other nameservers if
	66	several are available. It has sensible handling of bad responses etc.
	67
	68	</ul>
	69
8e5a4960	70	<h2>DNS utility programs</h2>
8e5a4960	71
630bf698	72	adns also comes with a number of utility programs for use from the
	73	command line and in scripts:
	74
	75	<ul>
	76
	77	<li><code>adnslogres</code> is a much faster version of Apache's
	78	logresolv program.
	79
	80	<li><code>adnsresfilter</code> is a filter which copies its input to
	81	its output, replacing IP addresses by the corresponding names, without
	82	unduly delaying the output. For example, you can usefully pipe the
	83	output of netstat -n, tcpdump -ln, and the like, into it.
	84
	85	<li><code>adnshost</code> is a general-purpose DNS lookup utility
8e5a4960	86	which can be used easily in from the command line and from shell
	87	scripts to do simple lookups. In a more advanced mode it can be used
	88	as a general-purpose DNS helper program for scripting languages which
	89	can invoke and communicate with subprocesses. See the
5a111351	90	<A href="http://www.chiark.greenend.org.uk/~ian/adns/docs/adnshost.txt">adnshost
b6922f88	91	usage message</A> for a summary of its capabilities.
630bf698	92
	93	</ul>
	94
630bf698	95	<h2>Documentation</h2>
	96
	97	I'm afraid there is no manual yet. However, competent C programmers
	98	should be able to use the library based on the
5a111351	99	<A href="http://www.chiark.greenend.org.uk/~ian/adns/docs/adns.h.txt">commented
8e5a4960	100	adns.h header file</A>, and the usage messages for the programs should
8e5a4960	101	be sufficient.
630bf698	102
	103	<h2>Feedback</h2>
	104
	105	I'd be pleased if you would let me know if you're using my library in
	106	your project, and what you think of it.
	107
	108	<p>
	109
2a9e6abd IJ	110	Bug reports should be reported to the
	111	<a href="http://debbugs.gnu.org/">GNU Debbugs</a>. Send an email
	112	to <code>submit@debbugs.gnu.org</code> and at the top of your email,
	113	in a paragraph of its own, write the single line
	114	<pre>
	115	Package: adns
	116	</pre>
	117	Your bug report will be published via to the adns-discuss list.
	118
	119	<p>
	120
	121	Feedback and discussion takes place on the <code>adns-discuss</code>
	122	list. You can mail me privately
	123	at <code>ijackson@chiark.greenend.org.uk</code>.
630bf698	124
	125	<h2>Mailinglists</h2>
	126
	127	I have set up mailinglists <code>adns-announce</code> and
	128	<code>adns-discuss</code>. The announcements list is moderated and
b6922f88	129	will contain only announcements of important bugs, new versions, etc.
630bf698	130
	131	<p>
	132
	133	There are
	134	<A href="http://www.chiark.greenend.org.uk/mailman/listinfo">archives
	135	and subscription web pages</A>, or you can subscribe by sending mail
	136	containing the word `subscribe' to
	137	<code>adns-announce-REQUEST@chiark.greenend.org.uk</code> or
	138	<code>adns-discuss-REQUEST@chiark.greenend.org.uk</code>.
	139
2a9e6abd	140	<h2>Documentation</h2>
630bf698	141
630bf698	142	<ul>
5a111351	143	<li><A href="http://www.chiark.greenend.org.uk/~ian/adns/docs/adns.h.txt">adns.h
2a9e6abd	144	API header file with documentation comments</A>
5a111351	145	<li><A href="http://www.chiark.greenend.org.uk/~ian/adns/docs/adnshost.txt">usage
2a9e6abd	146	message for adnshost</A>
630bf698	147	</ul>
630bf698	148
2a9e6abd IJ	149	<h2>Download and source code</h2>
2a9e6abd IJ	150
ea5ac657	151	<ul>
2a9e6abd IJ	152	<li>The <A href="http://www.chiark.greenend.org.uk/~ian/adns/adns.tar.gz">current
	153	release</A> as a gzipped tarfile.
	154	<li><A href="http://www.chiark.greenend.org.uk/~ian/adns/ftp/">Previous
827228ec	155	versions</A> and other files (including OpenPGP signatures).
2a9e6abd IJ	156	<li><A href="http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git/adns.git/">master
2a9e6abd IJ	157	git (version control) repository browser</a>.
ea5ac657	158	</ul>
ea5ac657	159
630bf698	160	adns is also available from the
	161	<A href="http://www.gnu.org/">GNU Project</A> FTP servers and their
	162	<A href="http://www.gnu.org/order/ftp.html">mirrors</A>.
	163
2a9e6abd	164	<h2>Installation note</h2>
b6922f88	165
e86aa5ef IJ	166	adns requires a real nameserver like BIND running on the same system
	167	or a nearby one, which must be willing to provide `recursive service'.
	168	I.e., adns is a `stub resolver'.
2a9e6abd IJ	169
	170	<p>
	171	adns requires that your real nameserver is on the same machine, or
	172	connected via a secure network, so that an attacker cannot fake the
	173	replies to adns's queries.
b6922f88	174
4fde3e92	175	<h2>References and related projects</h2>
4fde3e92	176
4f85494a	177	<ul>
1f2daabb	178	<li><a href="http://code.google.com/p/adns-python">Python bindings</a>
4f85494a	179	by Andy Dustman.
2a9e6abd IJ	180	<!-- <li><a href="http://cryp.to/hsdns/">Haskell bindings</a>
	181	by Peter Simons. -->
	182	<li><a href="http://www.lysator.liu.se/liboop/">liboop event loop library</a>
	183	has a built-in binding for adns.
4f85494a	184	<li><a href="http://adns.jgaa.com/">port to MS Visual Studio 6 C++</a>
217cfd38	185	by Jarle Aase.
4f85494a	186	</ul>
4fde3e92	187
630bf698	188	<h2>Copyright and licensing</h2>
630bf698	189
baa953c9	190	<kbd>adns</kbd> is Copyright 1997-2000,2003,2006,2014-2016 Ian Jackson,
2a9e6abd IJ	191	Copyright 2014 Mark Wooding, Copyright 1999-2000,2003,2006 Tony Finch,
2a9e6abd IJ	192	and Copyright (C) 1991 Massachusetts Institute of Technology.
630bf698	193
	194	<p>
	195
	196	<kbd>adns</kbd> is free software; you can redistribute it and/or modify
	197	it under the terms of the GNU General Public License as published by
2a9e6abd	198	the Free Software Foundation; either version 3 of the License, or (at
630bf698	199	your option) any later version.
	200
	201	<p>
	202
	203	This program and documentation is distributed in the hope that it will
	204	be useful, but <em>without any warranty</em>; without even the implied
	205	warranty of <em>merchantability</em> or <em>fitness for a particular
	206	purpose</em>. See the
5a111351	207	<A href="http://www.chiark.greenend.org.uk/~ian/adns/docs/COPYING.txt">GNU
630bf698	208	General Public License</A> for more details.
	209
	210	<p>
	211
	212	You should have received a copy of the GNU General Public License
	213	along with <kbd>adns</kbd>, or one should be available above; if not,
2a9e6abd IJ	214	write to the <A href="http://www.fsf.org/">Free Software Foundation</A>
2a9e6abd IJ	215	or email <code>ijackson@chiark.greenend.org.uk</code>.
630bf698	216
	217	<p>
	218
	219	<hr>
2a9e6abd	220	Ian Jackson / <tt>ijackson@chiark.greenend.org.uk</tt>.
630bf698	221	<p>
	222
	223	<A href="http://www.gnu.org/">GNU home page</A>;
	224	<A href="http://www.chiark.greenend.org.uk/">chiark home page</A>;
	225	<A href="/">site or mirror home page</A>
	226	<p>
	227
baa953c9	228	This web page is Copyright (C)1996-2005,2014-2016 Ian Jackson. See the
630bf698	229	<A href="http://www.chiark.greenend.org.uk/~ian/sw-www-copy.html">Copyright/acknowledgements</A>.
630bf698	230
	231	</body>
	232	</html>