Email Is So Simple … or Is It?
In normal people eyes, email seems so simple. You fill in the email address of the person to whom you want to send the email, write down the message and then click “Send”.
All done…or Just a beginning?
In reality, sending your email off into the Internet is a bit like sending Little Red Riding Hood into the Deep Dark Woods. You never know what might happen.
The total mechanism under the hood is much more complicated than you can image. Many components will be involved in whole email transfer process:
Main User Agent (MUA): It’s the application the originating sender uses to compose and read email, such as Outlook, Mail.app, Thunderbird, etc.
Mail Delivery Agent(MDA): It’s the component that is responsible for the delivery of email to a local users mailbox.
Mail Transfer Agent(MTA): It’s email transfer applications, sending the email to the correct destination. such as Exchange Server, Postfix, Sendmail, etc.
Visualize Email Routing
Each point stands for one server, and each line with arrow stands for one hop.
The color of line indicates whether message has been transferred in a safe channel(encrypted, shown in Green) or just in naked(plain text, shown in Red).
When your mouse hovers on each point, it will display the IP address of specific Server.
With Mr. Post, you can read email routing map clearly. And you should pay more attention on those transferred in plain text, passed many hops, sent from unknown region or countries.