Comments on: How Does An Email Server Work? [Technology Explained]

By: Subramanian

Subramanian — Fri, 21 Aug 2009 09:08:36 +0000

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By: Jim Hubbard

Jim Hubbard — Thu, 20 Aug 2009 18:12:13 +0000

In my experience, the biggest roadblock to implementing IMAP for most small businesses is the mailbox size.

IMAP keeps everything on the server and will quickly eat up most hosted email plans’ space if not watched carefully.

If it was unlimited on space – it would be nearly perfect.

By: find mail server

find mail server — Thu, 20 Aug 2009 17:37:47 +0000

IMAP4 certainly seems more advantagous over POP3 if you can access it from anywhere with an internet connection, although I do not like the idea it is slower.

By: Saikat

Saikat — Wed, 19 Aug 2009 12:26:54 +0000

The general parlance is SMTP server and POP3 server. Even on the same ‘database’ they are different server components and are therefore called as SMTP server and POP server.About your last point…I have mentioned that an email is relayed to the destination through several hops.

By: Saikat

Saikat — Wed, 19 Aug 2009 12:04:41 +0000

Yes, Jim that’s true. Most modern day email services have this option. The intention was to give a simplistic standard definition of the difference between POP3 and IMAP. Client and mail serve interactions are inherently more complex. Of course, without mentioning POP3 UIDL commands,I could have clarified the process bit more.

By: Jim Hubbard

Jim Hubbard — Tue, 18 Aug 2009 23:29:27 +0000

“An email client connects to the POP3 server and tells it to allow download of the email. Once downloaded to the local machine, POP3 mailboxes do not retain a copy of the email. Thus, you cannot check your emails from another PC as it has already been downloaded.”

This is simply not true. Modern email clients have settings to tell POP3 servers to keep their emails on the server. They can choose to keep them there until they delete the email from their email client or they can choose to have the emails live on the server for X days and then be deleted automatically.

By: annoyed

annoyed — Tue, 18 Aug 2009 21:46:38 +0000

This article should be rewritten. It is misleading and confused.
A protocol is something that is use by both sides, so you cannot say that an SMTP server is talking to a POP3 server. They are both using the same protocol or they are not talking at all.

WIKI says
While electronic mail servers and other mail transfer agents use SMTP to send and receive mail messages, user-level client mail applications typically only use SMTP for sending messages to a mail server for relaying. For receiving messages, client applications usually use either the Post Office Protocol (POP) or the Internet Message Access Protocol (IMAP) to access their mail box accounts on a mail server.

So according to wiki, POP3 and IMAP are used between clients and their server.

so client a -> (POP3) -> server A -> (SMTP) -> server B -> (POP3) -> client b

You are also confusing servers and protocols – you say that the SMTP server gives the mail to the POP3 server. That is not accurate. Both protocols are used on the same data-base, why call them separate servers.

And most important – according to you the sender server communicates directly to the receiver server, that is not how the internet works – packages are send in the general direction of the target and along the way pass other servers that move them on. Those other servers on the way, can and DO READ YOUR EMAIL. Of course, that is not supposed to happen, but can happen which is why email is NOT SECURE.