Answer by thenewasker for How to send mail from the command line?

I want to add another quite simple yet interesting way to do, provided by AWS (link)

So, you need to prepare this text file, save it as input.txt. Please remember to change the values:

• Replace example.com with your sending domain.

• Replace Base64EncodedSMTPUserName with your base64-encoded SMTP username.

• Replace Base64EncodedSMTPPassword with your base64-encoded SMTP password.

• Replace sender@example.com with the email address you are sending from. This identity must be verified.

• Replace recipient@example.com with the destination email address. If your Amazon SES account is still in the sandbox, this address must be verified.

  EHLO example.comAUTH LOGINBase64EncodedSMTPUserNameBase64EncodedSMTPPasswordMAIL FROM: sender@example.comRCPT TO: recipient@example.comDATAFrom: Sender Name <sender@example.com>To: recipient@example.comSubject: Amazon SES SMTP TestThis message was sent using the Amazon SES SMTP interface..QUIT

• To send using explicit SSL over port 587 – Enter the following command:

  openssl s_client -crlf -quiet -starttls smtp -connect smtp-server-endpoint:587 < input.txt

• To send using implicit SSL over port 465 – Enter the following command:

  openssl s_client -crlf -quiet -connect smtp-server-endpoint:465 < input.txt