This is a small bash script for testing relaying on mailservers without having to go through the whole 'mail from:' 'rcpt to:' payload process by hand.
-remote
The SMTP remote to connect to
-from
The 'From:' address
-to
The 'To:' address
-subject
The 'Subject:' line
-body
The message Body
-attachment
Attach a file
-starttls
Use openssl s_client with -starttls smtp and -crlf for the remote.
Includes -verify_return_error which will error and exit if we cannot verify the remote certificate.