LDAP + Windows 2003 Domain Authentication

Hi,

Firstly i dont know if this is the right place to post, but it seemed to fit. Secondly i dont know if anyone can help but its worth a shot.

My company uses alot of externally hosted customer relations management software, and task tracking etc. All of which is Open source and supports LDAP Authentication. Currently everyone who uses the software has a different user account for each application and a different password, excluding the ones within our domain. Our web server is externally hosted for security more than anything that and we cant get a fast enough upload speed on any lines comming into the buidling (max of 512k, and we can get 2000 visitors to our site alone in an hour).

So we are looking at implementing LDAP to authenticate our users with one username and password for everything, the problem with this is our web-server is on a public network and our domain server on a private one. I was wondering if anybody knows of a secure way to connect from our web server to our domain server. so that we can implement LDAP on all of our web-applications.

Thanks Alot

Alan Graham