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    copied!<p>Once again, thanks to the guidance of the people here, I've found an answer. The Java program above works when I do the following:</p> <pre><code>java -Djava.net.preferIPv4Stack=true DomainResolutionTest </code></pre> <hr> <p>Details:</p> <pre><code>jgreenwood@jeg-ubuntu64:~$ java -Djava.net.preferIPv4Stack=true DomainResolutionTest www.google.com/209.85.225.106 jgreenwood@jeg-ubuntu64:~$ java DomainResolutionTest ERROR: www.google.com java.net.UnknownHostException: www.google.com at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method) at java.net.InetAddress$1.lookupAllHostAddr(InetAddress.java:849) at java.net.InetAddress.getAddressFromNameService(InetAddress.java:1200) at java.net.InetAddress.getAllByName0(InetAddress.java:1153) at java.net.InetAddress.getAllByName(InetAddress.java:1083) at java.net.InetAddress.getAllByName(InetAddress.java:1019) at java.net.InetAddress.getByName(InetAddress.java:969) at DomainResolutionTest.main(DomainResolutionTest.java:12) </code></pre> <p>It turns out that there is a bug in the IPv6 stack. There are a couple of posts that led me to this conclusion:</p> <p><a href="http://uclue.com/?xq=2127" rel="nofollow noreferrer">http://uclue.com/?xq=2127</a></p> <p><a href="http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=477211" rel="nofollow noreferrer">http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=477211</a></p> <p><a href="https://answers.launchpad.net/ubuntu/+question/23024" rel="nofollow noreferrer">https://answers.launchpad.net/ubuntu/+question/23024</a></p> <p>I sure hope I don't have to add the IPv4 crap in every time I run a Java app. The final solution may be in the second link - a missing package. We shall see.</p> <blockquote> <p>Debian Bug report logs - #477211 ia32-sun-java6-bin: Needs to depend on lib32nss-mdns ... Cannot resolve domain names. Resolve fine on the rest of the system, have not tested with other JDK's. Installed from package and set with update-java-alternatives.</p> <p>DNS works for everything else on my system. Running on Debian 2.6.23-AMD64. Have tried both Lenny packages and Sid packages. Works as expected with sun-java6-bin, fails with ia32-sun-java6-bin. Arg. ... If you hit java with strace you'll see that it is trying to use libnss_mdns4_minimal.so.2, which is available in the package lib32nss-mdns. You should add a dependency on that to fix the bug.</p> <p>Same thing happens for sun-java6-bin - libnss-mdns is used here.</p> </blockquote> <p>The package is indeed missing on my machine:</p> <pre><code>jgreenwood@jeg-ubuntu64:~$ dpkg -L lib32nss-mdns Package `lib32nss-mdns' is not installed. Use dpkg --info (= dpkg-deb --info) to examine archive files, and dpkg --contents (= dpkg-deb --contents) to list their contents. </code></pre> <p>Either way, I hope this post helps someone else, because this was a major PITA to figure out.</p>
 

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