After following ISPconfig ubuntu guide - server is an open relay

[lspdev]

Hi

I do not know what you need, but after following this guide:
http://www.howtoforge.com/perfect-se...10-ispconfig-3

Which was done months ago, and has been working fine.
Today I decided to experiment with the idea of certificates from another guide on howtoforge...
I ran some tests and have found that since day one my server is open for abuse.

Basically I can log into the server using any mail client, any email address and no authentication and am able to sent email on port 25 to any domain....!!!

This is not good...

Please could someone help guide me to resolve this... from what I can see - It looks like it should not allow this, but it is...

thanks