How Email Works

We explains how an email can cross multiple networks and entire continents in just a few seconds.

An email is an electronic text message constructed and sent through an email client (such as Microsoft Outlook). Once written, the sending process begins, with the email client connecting to a simple mail transfer protocol (SMTP) server via the internet and through a DSL or line modem. The client then communicates with the SMTP part of your designated email server (for instance, GoogleMail) through a dedicated port.

During the transmission between your email client and server, your email client relays the header information of your email – in particular the recipient’s address and the contents within the email body. At this point the SMTP converts the information to a TXT file to send across the web.

Based on the header information within your email, the SMTP server then contacts the recipient’s correct email server. Using the sign as a divider, the SMTP takes the second part of the address to determine the location of the recipient’s server.

If the domain name is the same as the sender’s, the SMTP simply transfers the email information across. If the domain name is different, the SMTP contacts a DNS (domain name system) server and requests the exact IP address for the relating domain name’s hosted email server, such as those provided by Fasthosts.

Once the IP address has been obtained, the sender’s SMTP server sends out a signal message to the recipient’s SMTP over the web and all its gateways informing them that they have received a message. From then, the two servers converse with each other and the email is transferred.

The TXT file converts back into its original form, dropping the message into the bottom of the addressee’s mailbox. Finally, when the recipient logs in to their email client, it connects to the internet and commands the recipient’s POP3/IMAP (post office protocol/internet message access protocol) server to download all pending messages for viewing on the local machine.

Emails step by step

1. Outgoing – Firstly the sender’s PC connects to an SMTP server to convert the email into transmit-able data.

2. Redirect – The SMTP determines if the recipient’s domain is the same as the sender’s. If so, it redirects it inter-domain.

3. Query – If the domain of the recipient is different, however, the SMTP server asks for its IP address via a DNS server.

4. Exchange – With the address acquired, the email is transferred between servers and then dropped into your mailbox.

5. Retrieve – On logging in to your email client, a command is sent to your post office protocol to download the message.