Can Private E-Mail Communities Keep Out The Spam?
Gated Email?? >Kool!!
By Larry Seltzer
September 23, 2003

People with money and influence, and who don't care for the outside element, can fence off their community from the rest of the world. Outsiders can get in, but only by passing through a security gate. A phenomenon similar to this is developing in the world of e-mail, especially corporate e-mail, and it could help limit spam for those involved.

The best candidates for such an implementation are the large, hosted spam services such as Postini and FrontBridge. The way these services work is that incoming e-mail passes through their servers and is filtered before it is sent to the client's servers. Technically, they hold the MX records for the client's mail domain.

At the same time, these companies have more than one client. Consider that since the spam services already have a private, trusted relationship routing e-mail to their client companies, any mail passing between them could be considered trusted. There's no real need to pass this mail through filters, assuming these clients are responsible organizations with some sort of internal e-mail controls.

It's sort of like a big white list, but more sophisticated because it looks at the routing of mail. Suppose I white-list the address [email protected] because I buy my wife flowers now and then, and that's the online flower shop's confirmation address (note to self: buy the wife some flowers). A spammer could get through to my Inbox by spoofing that address in the From: field. But if my gateway spam blocker would check the referring server against a white list of clean servers, my blocker wouldn't be fooled by a simple From: spoof attempt.

Now, a spam message with truly-spoofed headers would be another matter. Still it would be very hard to get an outside message through this network and have it appear as of it was completely internal. In fact, I doubt anyone could do it.

At the same time, my point about responsible organizations with internal controls is really important. Some of the hosted services work with ISPs and other public mail services, the most famous being Hotmail's use of Larry Seltzer has worked in and written about the computer industry since 1983.


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