The POP Proxy Service

An Internet Service Provider (ISP) or Mail Hosting company normally provides its customers with a Post Office Protocol (POP3) mailbox, from which Internet email messages can be retrieved by a desktop email-reader program like Microsoft Outlook.

Incidentally, your ISP also provides a Simple Message Transfer Protocol (SMTP) server for outgoing mail (i.e. handling messages sent from your desktop email program).  However, this is usually housed on a different server, and normally has no relevance to the downloading of inbound messages destined for your email address.

Your desktop email program retrieves incoming mail by connecting to your POP3 server.  To do so, it looks up the internet address of the "POP Host" setting in your email program, e.g. pop3.someISP.net, and logs on to this server with the User Name and Password settings stored in your email account configuration settings.  Any new messages are then downloaded, and are usually deleted from the POP server after a successful retrieval.

In the above diagram, you can see how Internet Email messages are normally transferred into a Mail Server (via SMTP), then downloaded to your desktop email program (via POP3).  There are often a number of additional steps to this process, particularly on the SMTP side of things, where a message may be "relayed" through various hops.  However, such details are not particularly relevant...

When configuring an email program to download your email via Death2Spam, you're simply "inserting" D2S into the message delivery chain, as depicted below.  To download (and classify) your email, a D2S server needs to know which POP3 server you use, and your POP account authentication (logon) information.  As a "proxy", it just collects messages on your behalf, scans for viruses, then classifies your email as good or junk, according to your personal preferences.

To retrieve messages from the correct mail host, you simply configure your email program to provide D2S with a slightly different "User Name".  This field is changed so that it contains both your User ID and the name of your POP3 server, separated by a colon (:) or at-sign (@) character.  It doesn't actually matter which format you use.

Now, you can simply collect your email exactly the same as usual, only you'll notice that spam is clearly identified by a special D2S tag in the Subject line.  And any viruses are blocked at the D2S server, even before your desktop Anti-Virus program knows they exist!

Note that you can revert the configuration settings of your email program at any time, or setup a second account, to once again download email directly from your ISP's mail server.  This is a very useful aspect of the proxy architecture, since you're always in control of your email and are never "locked in" to some proprietory anti-spam solution.