[Webgate]: Configure ProxyPassMatch Directive -> Required for Apache/OHS Internal Redirect Calls

Potential Problem :

When webgate identifies an error/exception (may be reported by OAM) , in this
case webgate fires an internal redirect request for "/oberr.cgi" & this
invokes an error handler.
This error handler is defined in the webgate.conf file.
<Location "/oberr.cgi">
SetHandler obwebgateerr
</Location>

But when the resource webgate is the proxy. In this case if webgate
identifies error/exception, it fires an internal redirect request. But the
error handler "obwebgateerr" is not invoked.

Potential Reason: 

When apache sends the internal redirect request in that case it sets "proxy-server" handler by itself.
Due to which the handler defined for "/oberr.cgi" is not set as already an
handler is set. This causes the request to be proxied to the backend server &
causes problem.

Solution:

It is required to set a "ProxyPassMatch" directive before the "ProxyPass"
directive in the conf file.
By setting this directive, it will not proxy for the "/oberr.cgi" request to
the backend server rather it will be served by the webgate itself.

Configuration to do:

1) Add the following directive in the conf file. Restart the Web Server:

ProxyPassMatch ^/oberr.cgi !

Syntax:
ProxyPassMatch [regex] !

The ! directive is useful in situations where you don't want to reverse-proxy.

Eg:

ProxyPassMatch ^/oberr.cgi !
ProxyPass / http://something.com/AuthenticationService/
ProxyPassReverse / http://something.com/AuthenticationService/


Enjoy :-)