Answer
SMTP is the name given to the protocol (or langauge) that is used to transfer email messages between computers. The language has only ten or so words and some additional enhancements (called Enhanced SMTP or ESMTP) to reduce bandwidth and improve performance.
SMTP stands for “Simple Mail Transport Protocol”. A conversation between two computers using SMTP might look something like:
Who |
SMTP |
English |
|---|---|---|
Computer 1 |
connect |
Call computer 2. |
Computer 2 |
220 |
Greetings. |
Computer 1 |
HELO | Hello, how are you? |
Computer 2 |
220 | I’m OK thanks. What would you like to do? |
Computer 1 |
I’d like to send some mail from X |
|
Computer 2 |
220 | Looks fine to me. |
Computer 1 |
RCPT | The message is going to Y. |
Computer 2 |
220 | Ok, I’ll except the mail from you. |
Computer 1 |
DATA | I’ll send the message itself then… |
Computer 2 |
342 | Great, send it and let me know when you have finnished. |
Computer 1 |
message | This is the message. |
Computer 2 |
220 | Excellent. I’ll deliver it for you. |
Computer 1 |
QUIT | Goodbye. |
Computer 2 |
220 | See you again some other time. |
As you can see, the protocol is very simple and allows messages to be transfered very simply. There are several points you should notice:
- There is no authentication or verification of who is sending the message. Gordano sell a product call GMS Anti-Spam which can add this feature.
- The message itself is not checked to ensure that it is valid. This means that messages can be “spoofed” or appear to be from someone other than the real sender.
- Enhanced SMTP (ESMTP) adds lots of additional features that are required to reduce bandwidth, reduce latency and enhance error recovery. ESMTP connections are initiated by replacing HELO in the example above with EHLO, the links below show the advanced options available with ESMTP. All GMS products support these options.
See Also:
Keywords:SMTP