smtp using exchange node

Question

I've created a website in ASP.Net 2.0 and there is a contact page which should send an email.

The webserver is on an exchange node so should act as a local smtp server.

However, in my we.config file i've tried all sorts but nothing seems to be working but it works locally.

I've tried:

I have no login credentials for the server so shouldn't need to specify any.