PHP mai() - Fails to send

Hi all,

I have set up a 10.6 server. Now the mail is running on the local network though not across the internet as I'm only running the DNS locally and not using a smtp relay.

However it works in the sense that if i have the email address say email@server.co.uk and I send a piece of mail to email@server.co.uk from email@server.co.uk then the mail comes through. I know it's just going from the client to the server and back but it works internally.

However I have set up the server for website building/testing. Now if I have a php script that when run on the server should send a message to email@server.co.uk then it won't come through. However the server creates the account _www@server.co.uk and sends it's self a bounce back email saying the mail system at host server.co.uk could not send the message.

So how do I get php's mail() function to work?

Cheers

Steve