I need information to close an open relay on a dedicated server
I have 10 domains configured using PLESK as virtual domains
I have appeared on some blacklists today and my mails are being rejected
It appears that anyuser AT [url removed, login to view] (this is the hostname of the MACHINE not any of the domains I use for web etc)
can send mails through the server
When mails are sent from any of the virtual domains they have to be authenticated and this is working fine.
How can I ensure mails are not sent like this from anyuser AT [url removed, login to view]
I require the information to do the work as I have full access to the machine myself.