Meaning of SMTP

The modern working world is hard to imagine without constant communication. Workflows and project ideas can be coordinated very quickly and easily via e-mail. The message is sent directly from the sender to the recipient so that the recipient can react promptly. The exchange of texts, diagrams and images is also very easy and effortless. You use a network protocol to send online data in an orderly manner. The SMTP model in particular has established itself here. But what exactly is this protocol about? You can find out more about this topic here.

  • The abbreviation SMTP stands for Simple Mail Transfer Protocol.
  • It is a network protocol.
  • SMTP is used for communication via email.
  • This specifies the framework conditions for the data exchange.

What is SMTP

In your daily work you need a network protocol to send e-mails. This is also used if you send data privately from home via a web server. Defined by abbreviationfinder, the abbreviation describes Simple Mail Transfer Protocol, in German: simple mail transfer protocol. This protocol defines certain rules that are adhered to when transmitting data via e-mail. As a result, predetermined framework conditions apply for communication between two different servers – but such a protocol is also used with several servers. The best-known and frequently used software in the SMTP area include:

  • Exim
  • Postfix
  • GroupWise
  • IBM Lotus Domino

How does SMTP work?

When sending e-mails, your laptop takes on the role of the SMTP client. You are now a user of the SMTP server. This server represents the outgoing server of the respective mail program. The mail you have written with possible file attachments is uploaded to this server in a first step . The SMTP server then establishes the connection to a DNS server. This takes over the contact to the target SMTP server. The e-mail can be saved in the respective memory on the destination server. The addressee downloads them and can also access the email attachments.

What status codes are there?

Different codes occur in communication between the mail client and the server.

  • With the status code 1XX, the mail server has approved the request, but has not yet started its own activity – a confirmation message is required.
  • The code 2XX means that the server is performing the tasks without errors.
  • 3XX states that although the requests have been received, additional data is required for the implementation.
  • The code 4XX indicates a temporary problem. Simply repeating the procedure can fix the error.
  • It looks different with a code 5XX: This states that the task cannot be carried out and will be canceled.

What is an SMTP server?

When communicating by e-mail, the SMTP server only has the task of sending and forwarding the sender’s e-mails. Own and external users are clearly separated. A special authentication mechanism ensures this. This gives access to the server only for authorized users. In this way it is possible to reduce annoying spam emails blocking the inbox. Thanks to the various ports, a simple firewall control can be used to prevent outgoing spam messages from your network without cutting the connection to the external SMTP servers.

What is the difference between SMTP, IMAP and POP?

While SMTP only ensures the sending and forwarding of your e-mails, the IMAP and POP protocols take on other tasks. You have to choose one of the two applications when you create an account with an email client such as Thunderbird. IMAP stands for Internet Message Access Protocol, POP stands for a Post Office Protocol. Both protocols regulate the receipt of emails. POP is the slightly older version. With this protocol, you save the incoming data on your computer and the hard drive; copies of the mails are on the server. IMAP users do not receive a backup of the messages, they work directly with the data on the server of the e-mail provider.

How has SMTP evolved?

SMTP was first published in 1980. The idea came from the computer scientist Jon Postel, who is also considered one of the pioneers of the modern Internet. His plan was to decouple e-mail communication from the FTP mail service that had been in use since 1973 . It was initially used as an extension of the UUCP, Unix to Unix Copy Protocol – the transmission protocol for the Unix operating system, which is now only used for connecting offline devices. Originally, SMTP worked exclusively as an ASCII protocol, so the transmission of binary data was not possible. Since the introduction of MIME (Multipurpose Internet Mail Extensions) as an extension of the Internet standard, binary files can be reproduced in ASCII.