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<p>On 5/08/2022 4:44 pm, Alan Bateman wrote:<br>
</p>
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cite="mid:5e0e4376-afec-4663-d44c-f61b53bec865@oracle.com">
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On 04/08/2022 23:24, <a class="moz-txt-link-abbreviated
moz-txt-link-freetext"
href="mailto:mark.yagnatinsky@barclays.com"
moz-do-not-send="true">mark.yagnatinsky@barclays.com</a> wrote:<br>
<blockquote type="cite"
cite="mid:MN2PR12MB36162731F151952E20C9048CF99F9@MN2PR12MB3616.namprd12.prod.outlook.com">
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<p class="MsoNormal">I suspect that this is the wrong list;
please redirect me if so.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The docs for this method:<o:p></o:p></p>
<p class="MsoNormal"><a
href="https://docs.oracle.com/en/java/javase/18/docs/api/java.base/java/net/InetAddress.html#getLocalHost()"
moz-do-not-send="true" class="moz-txt-link-freetext">https://docs.oracle.com/en/java/javase/18/docs/api/java.base/java/net/InetAddress.html#getLocalHost()</a><o:p></o:p></p>
<p class="MsoNormal">say that it “Returns the address of the
local host. This is achieved by retrieving the name of the
host from the system, then resolving that name into an
InetAddress.”<o:p></o:p></p>
<p class="MsoNormal">This is true enough in simple cases, but
horribly misleading in non-trivial cases.<o:p></o:p></p>
<p class="MsoNormal">As far as I can tell it can’t return “the
address” because the local host may have multiple addresses.<o:p></o:p></p>
<p class="MsoNormal">Instead it returns “an address” of the
local host. My laptop right now has 3 addresses: IPv6
loopback, IPv4 from home WiFi, and IPv4 from company network
via VPN.<o:p></o:p></p>
<p class="MsoNormal">As far as I can tell (please correct me
if I’m wrong!!) if there are multiple addresses, the current
implementation makes no effort to pick a more “useful” one.<o:p></o:p></p>
<p class="MsoNormal">Instead, it takes whatever addresses it
gets from the OS and returns the first one.<o:p></o:p></p>
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You need to click through to the Networking Properties to read
more about configuration. The long standing default has been to
prefer IPv4 over IPv6 addresses. The OpenJDK net-dev mailing list
is the place to follow-up on this.<br>
<br>
-Alan<br>
</blockquote>
<p>Set the following property to prefer IPv6:</p>
<p>java.net.preferIPv6Addresses=TRUE</p>
<p>In our software we also use this property to determine whether to
prefer IPv4 or IPv6, eg multicast.
<a class="moz-txt-link-freetext" href="https://github.com/pfirmstone/JGDMS/blob/trunk/JGDMS/jgdms-discovery-providers/src/main/java/org/apache/river/discovery/x500/sha512withrsa/package.html">https://github.com/pfirmstone/JGDMS/blob/trunk/JGDMS/jgdms-discovery-providers/src/main/java/org/apache/river/discovery/x500/sha512withrsa/package.html</a></p>
<p>It's always good to utilise existing properties when possible.<br>
</p>
<pre class="moz-signature" cols="72">--
Regards,
Peter</pre>
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