mdw@git.distorted.org.uk Git - adns/blob - README

   1
   2                                    GNU adns
   3
   4    Advanced, easy to use, asynchronous-capable DNS client library and
   5    utilities.
   6
   7    adns is a resolver library for C (and C++) programs, and a collection
   8    of useful DNS resolver utilities. In contrast with the existing
   9    interfaces, gethostbyname et al and libresolv, it has the following
  10    features:
  11      * It is reasonably easy to use for simple programs which just want
  12        to translate names to addresses, look up MX records, etc.
  13      * It can be used in an asynchronous, non-blocking, manner. Many
  14        queries can be handled simultaneously.
  15      * Responses are decoded automatically into a natural representation
  16        for a C program - there is no need to deal with DNS packet
  17        formats.
  18      * Sanity checking (eg, name syntax checking, reverse/forward
  19        correspondence, CNAME pointing to CNAME) is performed
  20        automatically.
  21      * Time-to-live, CNAME and other similar information is returned in
  22        an easy-to-use form, without getting in the way.
  23      * There is no global state in the library; resolver state is an
  24        opaque data structure which the client creates explicitly. A
  25        program can have several instances of the resolver.
  26      * Errors are reported to the application in a way that distinguishes
  27        the various causes of failure properly.
  28      * Understands conventional resolv.conf, but this can overridden by
  29        environment variables.
  30      * Flexibility. For example, the application can tell adns to: ignore
  31        environment variables (for setuid programs), disable hostname
  32        syntax sanity checks to return arbitrary data, override or ignore
  33        resolv.conf in favour of supplied configuration, etc.
  34      * Believed to be correct ! For example, will correctly back off to
  35        TCP in case of long replies or queries, or to other nameservers if
  36        several are available. It has sensible handling of bad responses
  37        etc.
  38
  39 DNS utility programs
  40
  41    adns also comes with a number of utility programs for use from the
  42    command line and in scripts:
  43      * adnslogres is a much faster version of Apache's logresolv program.
  44      * adnsresfilter is a filter which copies its input to its output,
  45        replacing IP addresses by the corresponding names, without unduly
  46        delaying the output. For example, you can usefully pipe the output
  47        of netstat -n, tcpdump -ln, and the like, into it.
  48      * adnshost is a general-purpose DNS lookup utility which can be used
  49        easily in from the command line and from shell scripts to do
  50        simple lookups. In a more advanced mode it can be used as a
  51        general-purpose DNS helper program for scripting languages which
  52        can invoke and communicate with subprocesses. See the [1]usage
  53        message for a summary of its capabilities.
  54
  55 Technical note
  56
  57    adns requires a real nameserver like [2]BIND or [3]Dents running on
  58    the same system or a nearby one, which must be willing to provide
  59    `recursive service'. I.e., adns is a `stub resolver'. All properly
  60    configured UN*X and GNU systems will already have such nameserver(s);
  61    they are usually listed in /etc/resolv.conf.
  62
  63 Documentation
  64
  65    I'm afraid there is no manual yet. However, competent C programmers
  66    should be able to use the library based on the [4]commented adns.h
  67    header file, and the usage messages for the programs should be
  68    sufficient.
  69
  70 Feedback
  71
  72    I'd be pleased if you would let me know if you're using my library in
  73    your project, and what you think of it.
  74
  75    If you are subscribed to adns-discuss please send feedback, including
  76    bug reports, there; otherwise send mail to
  77    adns-bugreports@chiark.greenend.org.uk. If you'd prefer that your
  78    message wasn't forwarded to the adns-bugreports list, send it to
  79    adns-maint@chiark.greenend.org.uk.
  80
  81 Mailinglists
  82
  83    I have set up mailinglists adns-announce and adns-discuss. The
  84    announcements list is moderated and will contain only announcements of
  85    important bugs, new versions, &c. The bug reports address mentioned
  86    above is also a mailing list; feel free to subscribe to it.
  87
  88    There are [5]archives and subscription web pages, or you can subscribe
  89    by sending mail containing the word `subscribe' to
  90    adns-announce-REQUEST@chiark.greenend.org.uk or
  91    adns-discuss-REQUEST@chiark.greenend.org.uk.
  92
  93 Download
  94
  95    Available for download from [6]chiark.greenend.org.uk are:
  96      * The [7]current beta version as a gzipped tarfile.
  97      * [8]adns.h API header file with comments (currently there is no
  98        manual, sorry).
  99      * All versions released so far are also available via [9]anonymous
 100        FTP.
 101      * A mirror of my CVS repository is available via rsync from
 102        rsync.chiark.greenend.org.uk::ftp/users/ian/cvs-pub/adns (use FTP
 103        first to find your way around), or via [10]cvsweb.
 104
 105    adns is also available from the [11]GNU Project FTP servers and their
 106    [12]mirrors.
 107
 108 Copyright and licensing
 109
 110    adns is Copyright 1997-2000 Ian Jackson, Copyright 1999 Tony Finch,
 111    and Copyright (C) 1991 Massachusetts Institute of Technology.
 112
 113    adns is free software; you can redistribute it and/or modify it under
 114    the terms of the GNU General Public License as published by the Free
 115    Software Foundation; either version 2 of the License, or (at your
 116    option) any later version.
 117
 118    This program and documentation is distributed in the hope that it will
 119    be useful, but without any warranty; without even the implied warranty
 120    of merchantability or fitness for a particular purpose. See the
 121    [13]GNU General Public License for more details.
 122
 123    You should have received a copy of the GNU General Public License
 124    along with adns, or one should be available above; if not, write to
 125    the [14]Free Software Foundation, 59 Temple Place - Suite 330, Boston,
 126    MA 02111-1307, USA, or email adns-maint@chiark.greenend.org.uk.
 127      _________________________________________________________________
 128
 129    [15]Ian Jackson / [16]adns-maint@chiark.greenend.org.uk; more [17]free
 130    software by me.
 131
 132    [18]GNU home page; [19]chiark home page; [20]site or mirror home page
 133
 134    This web page is Copyright (C)1996-2000 Ian Jackson. See the
 135    [21]Copyright/acknowledgements.
 136
 137    Use any browser - [22]Campaign for a non-browser-specific WWW
 138
 139 References
 140
 141    1. http://www.chiark.greenend.org.uk/~ian/adns/usage/adnsresfilter_usage.text
 142    2. http://www.isc.org/view.cgi?/products/BIND/index.phtml
 143    3. http://www.dents.org/
 144    4. http://www.chiark.greenend.org.uk/~ian/adns/adns.h.txt
 145    5. http://www.chiark.greenend.org.uk/mailman/listinfo
 146    6. http://www.chiark.greenend.org.uk/~ian/adns/
 147    7. http://www.chiark.greenend.org.uk/~ian/adns/adns.tar.gz
 148    8. http://www.chiark.greenend.org.uk/~ian/adns/adns.h.txt
 149    9. ftp://ftp.chiark.greenend.org.uk/users/ian/adns/
 150   10. http://www.chiark.greenend.org.uk/ucgi/~ijackson/cvsweb/adns/
 151   11. http://www.gnu.org/
 152   12. http://www.gnu.org/order/ftp.html
 153   13. http://www.chiark.greenend.org.uk/~ian/COPYING.txt
 154   14. http://www.fsf.org/
 155   15. http://www.chiark.greenend.org.uk/
 156   16. mailto:adns-maint@chiark.greenend.org.uk
 157   17. http://www.chiark.greenend.org.uk/~ian/software/
 158   18. http://www.gnu.org/
 159   19. http://www.chiark.greenend.org.uk/
 160   20. file://localhost/
 161   21. http://www.chiark.greenend.org.uk/~ian/sw-www-copy.html
 162   22. http://www.anybrowser.org/campaign/