dnsjava v1.5

http://www.xbill.org/dnsjava
http://www.dnsjava.org/

Author:

Brian Wellington (bwelling@xbill.org)
December 9, 2003

Overview:

dnsjava is an implementation of DNS in Java.  It supports all of the common
record types, the DNSSEC types, and unknown types.  It can be used for queries,
zone transfers, and dynamic updates.  It includes a cache which can be used by
clients, and an authoritative only server.  It supports TSIG authenticated
messages, partial DNSSEC verification, and EDNS0.  It is fully thread safe.

dnsjava was started as an excuse to learn Java.  It was useful for testing new
features in BIND without rewriting the C resolver.  It was then cleaned up and
extended in order to be used as a testing framework for DNS interoperability
testing.  The high level API and caching resolver were added to make it useful
to a wider audience.  The authoritative only server was added as proof of
concept.


Getting started:

Run 'make' or 'ant' from the toplevel directory to build dnsjava.  JDK 1.2
or higher is required.

To compile dnssec support (org.xbill.DNS.security), the Java Cryptography
Extensions are required.  Run 'make dnssec' or 'ant dnssec' to compile this
package.  TSIG support is separate from dnssec support, and does not require
that dnssec support be built.

Limitations:

There's no way to determine what the local nameserver is at runtime from within
the JVM.  First, the property 'dns.server' (a comma delimited list) is
checked.  These can either be IP addresses or hostnames (which are resolved
using Java's built in DNS support).  If the underlying OS is unix-based, the
dnsjava package can parse /etc/resolv.conf and determine the nameservers.  If
the underlying OS is Windows, winipcfg/ipconfig can be called and the output
parsed.  Note that this may fail for non-English versions of Windows.
Otherwise, or if these attempts fail, the default nameserver is
"localhost".  This is unavoidable.  Unfortunately, I have no idea how to
determine the nameserver for any other OSes.  Contributions of code
are welcome (see org/xbill/DNS/FindServer.java for the basic structure).

On some machines, InetAddress.getLocalHost() returns 127.0.0.1.  This is
usually caused by a bug in the JVM, and often happens when the machine has
a dynamic address and its hostname is not in DNS.  This breaks the (mostly
undocumented) feature that the @me@ variable can be used in the textual form
of an A record to indicate the local address.  If InetAddress.getLocalHost()
doesn't work, a RuntimeException will be thrown.  This should be fixable
if/when dnsjava requires Java 1.4.

Not all of the record types are supported.  Most types that are not supported
are either deprecated or rarely used.  Adding support for a new type is not
difficult, and usually requires no changes to any existing files.  If you want
to see a new type supported, send a patch or just ask.

The underlying platform must use an ASCII encoding of characters.  This means
that dnsjava will not work on OS/390, for example.


Additional documentation:

Javadoc documentation is provided in the doc/ subdirectory of binary
distributions, and can be built with 'make docs' or 'ant docs'.


License:

dnsjava is placed under the BSD license.  Several files are also under
additional licenses; see the individual files for details.

Copyright (c) 1999-2003, Brian Wellington
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

    * Redistributions of source code must retain the above copyright notice,
      this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright notice,
      this list of conditions and the following disclaimer in the documentation
      and/or other materials provided with the distribution.
    * Neither the name of the dnsjava project nor the names of its contributors
      may be used to endorse or promote products derived from this software
      without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


Final notes:

 - Thanks to Network Associates, Inc. for sponsoring some of the original
   dnsjava work in 1999-2000.

 - Thanks to Nominum, Inc. for sponsoring some work on dnsjava from 2000-2003.