Relaying not allowed

I have set up Outlook Express with all the account settings which all work fine, when I try and send a message to one of my other accounts not part of ISPConfig I get:

The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was '[email protected]'. Subject 'Test', Account: 'pop.touchonehosting.co.uk', Server: 'smtp.touchonehosting.co.uk', Protocol: SMTP, Server Response: '554 <[email protected]>: Relay access denied', Port: 25, Secure(SSL): No, Server Error: 554, Error Number: 0x800CCC79

Is there a setting somewhere in my mail config to allow this to go through.

Thanks

 

In my main.cf file I have a line "relayhosts = " does something need to be after the = sign.

Thanks

 

ISPConfig uses Saslauthentication, you need to setup exchange to authenticate with SMTP to be able to relay outside your own server.

smtprelay = means a server which the postfix MTA will use to deliver all mail to and let to handle maildelivery for outgoing networks.

What you are looking for would be
mynetworks = 127.0.0.1/32

means it will accept anything from localhost
add more networks if you want to allow them without authentication
mynetworks = 127.0.0.1/32, 213.122.112.0/24
would allow any ip on 213.112.112.0 subnet.

 

I want to only allow authenticated users to relay messages to other domains from outside the current domain.

If you know what I mean.

 

You must enable "Server requires authentication." in your email client, that's all.