I think if you read IBM's own Websphere server documentation, you'll find that they suggest you use the Apache httpd server, rather than their own built-in http server in Websphere, for serious performance etc.



And they give you instructions for how to do it.



I think their own built-in httpd server, inside Websphere, is actually based on a rather old version of the Apache httpd in the first place, lacking all the enhancements it's gained in recent years.



It's been a while since I read the documents in question, but it was what you get in searching for httpd, web proxying, etc., in the documentation for Websphere server version 5.1, I think.