telnet mail.domain.ext 25
You should receive a reply like:
Connected to mail.domain.ext.
Escape character is ‘^]’.
220 mail.domain.ext ESMTP Sendmail ?version-number?; ?date+time+gmtoffset?
You will then need to declare where you are sending the email from:
HELO local.domain.name – don’t worry too much about your local domain name although you really should use your exact fully qualified domain name as seen by the outside world the mail server has no choice but to take your word for it as of RFC822-RFC1123.
This should give you:
250 mail.domain.ext Hello local.domain.name [loc.al.i.p], pleased to meet you
Now give your email address:
(On many mailservers the space after the : is required rather that optional. Thanks to Justing Goldberg)
MAIL FROM: firstname.lastname@example.org
250 2.1.0 email@example.com… Sender ok
If it doesn’t please see possible problems.
Now give the recipients address:
RCPT TO: firstname.lastname@example.org
250 2.1.0 email@example.com… Recipient ok
If it doesn’t please see possible problems. Note Google mail servers require < and > around the email address (thanks to Paul Beattie).
To start composing the message issue the command DATA
If you want a subject for your email type Subject:-type subject here- then press enter twice (these are needed to conform to RFC 882)
You may now proceed to type the body of your message (e.g. hello firstname.lastname@example.org from email@example.com)
To tell the mail server that you have completed the message enter a single “.” on a line on it’s own.
The mail server should reply with: 250 2.0.0 ???????? Message accepted for delivery
You can close the connection by issuing the QUIT command.
The mailserver should reply with something like:221 2.0.0 mail.domain.ext closing connection
Connection closed by foreign host.