Embedded Crowd Does Not Respect the ProxyHost Parameter When Connecting to LDAP/Crowd/JIRA

Summary

The embedded crowd library that comes with applications such as Confluence/JIRA/Stash does not respect the proxyHost parameter (used to connect to forwarding proxies), when trying to obtain users from another server (such as JIRA/Crowd/LDAP)

Environment

You have an environment that requires forwarding proxy to forward requests from Confluence/JIRA/Crowd to another server (where the users are stored, could be AD/Crowd/LDAP/JIRA)

Steps to Reproduce

1. Setup Confluence
2. Add the proxyHost parameter to Confluence's JVM parameters (example):

   -Dhttp.proxyHost=proxy.test.com -Dhttp.proxyPort=3128
   

   Modify it accordingly to fit your forwarding proxy configuration

3. Make sure JIRA is contactable from Confluence, only via the forwarding proxy
4. Start up Confluence, and setup JIRA user management. This will fail with this error:

   2015-12-01 12:57:58,790 ERROR [TP-Processor10] [crowd.embedded.admin.ConfigurationController] onSubmit Configuration test failed for user directory: [ JIRA Server], type: [ CROWD ]
    -- referer: https://confluence.test:8090/plugins/servlet/embedded-crowd/configure/jira/?xsrfTokenName=atl_token&xsrfTokenValue=83233435434634b3b60c3d600bfa4ae2ba546 | url: /plugins/servlet/embedded-crowd/configure/jira/ | userName: test
   com.atlassian.crowd.exception.runtime.OperationFailedException: org.apache.http.conn.HttpHostConnectException: Connect to jira.test:8010 [jira.test/12.12.24.25] failed: Network is unreachable
   	at com.atlassian.crowd.embedded.core.CrowdDirectoryServiceIm
   

5. Setup Application Links with JIRA via the same URL. This will succeed (proof that only embedded Crowd is affected)

Workaround

No known workaround, except to make sure that JIRA/Crowd/LDAP is contactable without the forwarding proxy