This issue applies to WLS plug-ins for Apache 2.2 on Windows only (not applicable for OHS or any other Listeners/Web Servers).
If an IPv6 address is specified for WebLogicHost/WebLogicCluster parameter, then WLS plug-in may be unable to resolve this IPv6 address. This is due to a bug in the APR library that is shipped Apache httpd 2.2.x (underlying APR library, libapr-1.dll), and is resolved in Apache httpd 2.2.24.