How Email Hosting Work

The way email works is the email host has two special computers, one called a SMTP (Simple Mail Transfer Protocol) server, the other one called a POP3 server. POP stands for Post Office Protocol. The SMTP server listens on port 25, a standard port for email transmission, while POP3 listens on port 110. Whenever you send email, your email client contacts the SMTP server to send the email. Here is what happens:

 

·        Let’s say you want to send an email to say jdoe. Let’s say your account name is hhusted. And let’s say you belong to AOL. So you set up your email client with the name of the mail server as mail.aol.com. When you create a message and direct it to go to jdoe, who has an account with say Earthlink, his server name will be mail.earthlink.com, the email client will connect to the mail server using port 25.

·        Then the client will tell the SMTP server the address of the sender and the receiver, and the body containing the message.

·        The SMTP server will take the “to” address (jdoe@earthlink.com) and break it down like this: the recipient’s name (jdoe), and the domain name (earthlink.com).

·        The SMTP server communicates with the Domain Name Server (DNS) to find the location or server for the host that the mail is going to. The DNS then supplies that info.

·        The SMTP then connects with the SMTP server at mail.earthlink.com and sends the exact same information to that mail server. Once the SMTP server receives the message and recognizes it, the server forwards the message to the POP server, which in turn puts the message in jdoe’s mailbox.