You can use
Mail relay testing
i think the reason why the open relay failed is because i cant actually send mails to the outside world just tried sending a mail to my gmail account and it failed giving and error
The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was 'email@example.com'. Subject 'hh', Account: 'x.x.x.x', Server: 'x.x.x.x', Protocol: SMTP, Server Response: '554 5.7.1
: Relay access denied', Port: 25, Secure(SSL): No, Server Error: 554, Error Number: 0x800CCC79
That is the response I would expect and it shows you can't send email to the outside world without authentication. As I've already said, logging in as a user to get email from your server means I would then be authenticated and I could send mail to the outside world.
ok now how do i resolve that i really appreciate your help really i know i have been a bit of a pain but i just want the server to be safe.
it was sending mails before i changed the host name and it stopped but i can receive mails