Manually testing an outgoing SMTP server
1) Open a command prompt (Start > Run > CMD > [press enter])
2) At the command prompt type:
TELNET mail.serverdomain.com 25 [press enter]
(Replace "mail.serverdomain.com" with the name of the SMTP server)
3) Wait for a "220 Ready" response from the server; if you do not get this response then you may have a firewall blocking port 25 or the mail server may be off line.
4) Type the following set of commands to test the server:
EHLO mail.serverdomain.com [press enter]
(Replace "mail.serverdomain.com" with the name of the SMTP server)
MAIL FROM:postmaster@serverdomain.com [press enter]
(Replace "postmaster@serverdomain.com" with YOUR email address)
RCPT TO:postmaster@serverdomain.com [press enter]
(Replace "postmaster@serverdomain.com" with a valid email address on the server; most servers have a "postmaster@" address)
DATA [press enter]
Subject:Email test - please reply [press enter, then press enter TWICE MORE]
Please reply to this email at postmaster@serverdomain.com [press enter]
(Replace "postmaster@serverdomain.com" with YOUR email address)
. [press enter, you may need to press enter again until you see "250 +OK" message]
QUIT