One SMTP server can handle email for multiple domain names ... [email protected]”, “Subject: Example subject” — which are followed by the actual body of the message.

In order to do this, we first need to figure out what our email server expects to see from a client. This can be done by connecting via telnet to our SMTP relay host and issuing the correct SMTP ...

Google offers an SMTP (Simple Mail Transfer Protocol ... by email gateways and spam filtering services. For example, the following email, spotted by Avanan, appears as if it comes from Trello.com ...