b6922f88 |
1 | <html> |
2 | <head> |
3 | <title>adns - advanced, alternative, asynchronous resolver</title> |
630bf698 |
4 | <link rev="made" href="mailto:adns-maint@chiark.greenend.org.uk"> |
5 | </head> |
6 | <body> |
7 | <h1>GNU adns</h1> |
8 | |
9 | <strong>Advanced, easy to use, asynchronous-capable DNS client |
10 | library and utilities.</strong> |
11 | |
b6922f88 |
12 | <!-- Note: this file is maintained in Ian Jackson's private CVS. --> |
13 | <!-- --> |
14 | <!-- It is served on the GNU site and also from my own system, --> |
15 | <!-- under the URL http://www.chiark.greenend.org.uk/adns/ --> |
16 | <!-- Please ensure that all links continine to be correct --> |
17 | <!-- both for www.gnu.org and chiark. --> |
18 | <!-- --> |
19 | <!-- $Id$ --> |
20 | |
630bf698 |
21 | <p> |
22 | |
8e5a4960 |
23 | adns is a resolver library for C (and C++) programs, and a collection |
b6922f88 |
24 | of useful DNS resolver utilities. |
25 | |
26 | |
27 | <h2>C library</h2> |
28 | |
29 | In contrast with the standard interfaces, gethostbyname et al and |
30 | libresolv, it has the following features: |
630bf698 |
31 | |
32 | <ul> |
33 | |
34 | <li>It is reasonably easy to use for simple programs which just want |
35 | to translate names to addresses, look up MX records, etc. |
36 | |
37 | <li>It can be used in an asynchronous, non-blocking, manner. Many |
38 | queries can be handled simultaneously. |
39 | |
40 | <li>Responses are decoded automatically into a natural representation |
41 | for a C program - there is no need to deal with DNS packet formats. |
42 | |
43 | <li>Sanity checking (eg, name syntax checking, reverse/forward |
44 | correspondence, CNAME pointing to CNAME) is performed automatically. |
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 | |
56 | <li>Understands conventional resolv.conf, but this can overridden by |
57 | environment variables. |
58 | |
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> |
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 |
b6922f88 |
90 | <A href="http://www.chiark.greenend.org.uk/~ian/adns/adnshost.txt">adnshost |
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 |
99 | <A href="http://www.chiark.greenend.org.uk/~ian/adns/adns.h.txt">commented |
8e5a4960 |
100 | adns.h header file</A>, and the usage messages for the programs should |
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 | |
110 | If you are subscribed to <code>adns-discuss</code> please send |
111 | feedback, including bug reports, there; otherwise send mail to |
112 | <code>adns-bugreports@chiark.greenend.org.uk</code>. If you'd prefer |
113 | that your message wasn't forwarded to the <code>adns-bugreports</code> |
114 | list, send it to <code>adns-maint@chiark.greenend.org.uk</code>. |
115 | |
116 | <h2>Mailinglists</h2> |
117 | |
118 | I have set up mailinglists <code>adns-announce</code> and |
119 | <code>adns-discuss</code>. The announcements list is moderated and |
b6922f88 |
120 | will contain only announcements of important bugs, new versions, etc. |
630bf698 |
121 | The bug reports address mentioned above is also a mailing list; feel |
122 | free to subscribe to it. |
123 | |
124 | <p> |
125 | |
126 | There are |
127 | <A href="http://www.chiark.greenend.org.uk/mailman/listinfo">archives |
128 | and subscription web pages</A>, or you can subscribe by sending mail |
129 | containing the word `subscribe' to |
130 | <code>adns-announce-REQUEST@chiark.greenend.org.uk</code> or |
131 | <code>adns-discuss-REQUEST@chiark.greenend.org.uk</code>. |
132 | |
133 | <h2>Download</h2> |
134 | |
135 | Available for download from |
136 | <A href="http://www.chiark.greenend.org.uk/~ian/adns/">chiark.greenend.org.uk</A> |
137 | are: |
138 | <ul> |
b6922f88 |
139 | <li>The <A href="http://www.chiark.greenend.org.uk/~ian/adns/adns.tar.gz">current |
140 | release</A> as a gzipped tarfile. |
630bf698 |
141 | <li><A href="http://www.chiark.greenend.org.uk/~ian/adns/adns.h.txt">adns.h</A> |
b6922f88 |
142 | API header file with comments, and |
aa3ffb57 |
143 | <A href="http://www.chiark.greenend.org.uk/~ian/adns/adnshost.txt">usage |
b6922f88 |
144 | message for adnshost</A> (currently there is no manual, sorry). |
630bf698 |
145 | <li>All versions released so far are also available via |
146 | <A href="ftp://ftp.chiark.greenend.org.uk/users/ian/adns/">anonymous |
d0ac9ea0 |
147 | FTP</A> and <A href="http://www.chiark.greenend.org.uk/~ian/adns/ftp/">HTTP</A>, |
630bf698 |
148 | <li>A mirror of my CVS repository is available via rsync from |
149 | <code>rsync.chiark.greenend.org.uk::ftp/users/ian/cvs-pub/adns</code> |
150 | (use FTP first to find your way around), or via |
151 | <A href="http://www.chiark.greenend.org.uk/ucgi/~ijackson/cvsweb/adns/">cvsweb</A>. |
152 | </ul> |
153 | |
154 | adns is also available from the |
155 | <A href="http://www.gnu.org/">GNU Project</A> FTP servers and their |
156 | <A href="http://www.gnu.org/order/ftp.html">mirrors</A>. |
157 | |
b6922f88 |
158 | <h2>Technical note</h2> |
159 | |
160 | adns requires a real nameserver like |
161 | <A href="http://www.isc.org/view.cgi?/products/BIND/index.phtml">BIND</A> |
162 | or |
163 | <A href="http://www.dents.org/">Dents</A> running on |
164 | the same system or a nearby one, which must be willing to provide |
165 | `recursive service'. I.e., adns is a `stub resolver'. All properly |
166 | configured UN*X and GNU systems will already have such nameserver(s); |
167 | they are usually listed in /etc/resolv.conf. |
168 | |
4fde3e92 |
169 | <h2>References and related projects</h2> |
170 | |
171 | There is a <a href="http://adns.jgaa.com/">port to MS Visual Studio 6 |
172 | C++</a> by Jarle Aase. |
173 | |
630bf698 |
174 | <h2>Copyright and licensing</h2> |
175 | |
b6922f88 |
176 | <kbd>adns</kbd> is Copyright 1997-2000 Ian Jackson, Copyright |
177 | 1999-2000 Tony Finch, and Copyright (C) 1991 Massachusetts Institute |
178 | of Technology. |
630bf698 |
179 | |
180 | <p> |
181 | |
182 | <kbd>adns</kbd> is free software; you can redistribute it and/or modify |
183 | it under the terms of the GNU General Public License as published by |
184 | the Free Software Foundation; either version 2 of the License, or (at |
185 | your option) any later version. |
186 | |
187 | <p> |
188 | |
189 | This program and documentation is distributed in the hope that it will |
190 | be useful, but <em>without any warranty</em>; without even the implied |
191 | warranty of <em>merchantability</em> or <em>fitness for a particular |
192 | purpose</em>. See the |
193 | <A href="http://www.chiark.greenend.org.uk/~ian/COPYING.txt">GNU |
194 | General Public License</A> for more details. |
195 | |
196 | <p> |
197 | |
198 | You should have received a copy of the GNU General Public License |
199 | along with <kbd>adns</kbd>, or one should be available above; if not, |
200 | write to the |
201 | <A href="http://www.fsf.org/">Free Software Foundation</A>, |
202 | 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA, |
203 | or email <code>adns-maint@chiark.greenend.org.uk</code>. |
204 | |
205 | <p> |
206 | |
207 | <hr> |
208 | <A href="http://www.chiark.greenend.org.uk/">Ian Jackson</A> / |
209 | <A href="mailto:adns-maint@chiark.greenend.org.uk"><tt>adns-maint@chiark.greenend.org.uk</tt></A>; |
210 | more <A href="http://www.chiark.greenend.org.uk/~ian/software/">free |
211 | software</A> by me. |
212 | <p> |
213 | |
214 | <A href="http://www.gnu.org/">GNU home page</A>; |
215 | <A href="http://www.chiark.greenend.org.uk/">chiark home page</A>; |
216 | <A href="/">site or mirror home page</A> |
217 | <p> |
218 | |
219 | This web page is Copyright (C)1996-2000 Ian Jackson. See the |
220 | <A href="http://www.chiark.greenend.org.uk/~ian/sw-www-copy.html">Copyright/acknowledgements</A>. |
221 | <p> |
222 | |
223 | Use any browser - |
224 | <A href="http://www.anybrowser.org/campaign/">Campaign for a non-browser-specific WWW</A> |
225 | |
226 | </body> |
227 | </html> |