Institutions typically use different ways (Shibboleth, LDAP, etc.) to authenticate users. It is difficult to achieve a one-size-fits-all deployment to address all the different authentication in OLE. This bottleneck can be cleared by using a reverse proxy.
Reverse Proxy
A reverse proxy server is a specialized web server that inspects incoming requests and forwards them to another internal web server after any local processing is completed. It also inspects and makes sure that any response from the internal web server containing URLs are updated with the proper host address.
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Apache versions prior to Apache 2.4.4 (especially Apache 2.2.x shipped with Red Hat Enterprise Linux 6.x) cannot forward PATCH requests via the AJP protocol, which can interfere with some of OLE's APIs. |
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If you are experiencing HTTP 501 ("Method Not Implemented") errors, this may be the cause. Check your Apache version and error logs for messages such as "ajp_marshal_into_msgb - No such method PATCH".
Possible Fixes
- Use mod_proxy_http instead of mod_proxy_ajp in your proxy setup.
- Use at least Apache 2.4.4 with mod_proxy_ajp.
- (Unverified) Use mod_jk instead of mod_proxy_ajp.