Wednesday 1 May 2019

Completely Disabling EPM from Using IPv6


IPv6 can be a real pain when configuring a Hyperion environment on Windows. Despite disabling all the tunnels and making changes in the registry (see previous blog post) the WebLogic applications will still sometimes bind to IPv6 addresses.

One thing you can do to disable IPv6 is change your "Listen" line in the OHS httpd.conf to mention the IP address, i.e.


Listen 22.11.35.91:19000

Please note when you do this you also need to add your server names and FQDNs to the hosts file - otherwise OHS may still resolve the IP addresses of servers to IPv6 and you see errors like this in the OHS logs:

'::1/28080; got exception 'CONNECTION_REFUSED [os error=0, line 1602 of URL.cpp]:

Even with the amendments to the OHS listen address and the hosts file, these won't fix the issue of WebLogic servers binding on IPv4 and IPv6 addresses. One thing we can do is disable IPv6 by creating a new "JVMOption" parameter in the registry, like so:



Well the registry changes don’t survive if you re-deploy the apps so I wanted to find another way, I think I have found it now.

If you create a new system variable called “JAVA_TOOL_OPTIONS” and give it the value "-Djava.net.preferIPv4Stack=true" it will get picked up by the WebLogic applications on next restart.





This looks like the best way of resolving the issue and making sure you avoid all IPv6-related errors in your environments.


Edit: you really, really, really need that OHS Listen address altered - otherwise it will lead to errors!

Edit 2: added a little section on further configuration in hosts file being required - what a hassle!