TLS Is a No-Brainer For Mail Servers

By Larry Seltzer  |  Posted 2004-12-12 Print this article Print

Opinion: There's no reason not to implement encryption between servers, even if it seems you're addressing a problem that doesn't exist.

Encryption has been an important feature of many Internet protocols for some time now. Transfers between mail servers havent historically been protected, but there is a protocol available to encrypt them, and everyone should now look to implement it. TLS (Transport Layer Security) is easy to use. Of course, how easy it is depends on the specifics of each server, but generally its little more than clicking a checkbox in the servers administrative console. You do need to get a certificate, but you dont necessarily need to have one held by a certificate authority. You can generate your own certificate for free, and in many ways this works just as well. The end result is that mail transfers on the Internet between servers will be encrypted, as opposed to the default of clear text. The protocol is set up to request an encrypted transfer and fall back to unencrypted if the recipient doesnt support encryption.
We know its easy to do, and as far as I can tell theres no downside. This is why secure managed e-mail provider Postini has announced that it will support TLS (which they call "Postini Auto-Encryption") for all outside mail interaction with their e-mail boundary service Perimeter Manager Enterprise Edition 5.2. Postini claims to be the fourth-largest e-mail provider, so this move should increase the amount of TLS in use on the Internet considerably.
Click here to read eWEEK Labs review of Postinis Perimter Manager. So theres no reason not to implement TLS, but whats the positive rationale for it? What problem does it solve? The obvious answer—the one you find in press releases—is that it secures the connection between two servers through encryption. The implication is that, absent the encryption, someone could "tap" the connection between those servers and read the data. Does this ever happen? I tried to find examples of it with no luck, but perhaps I didnt search cleverly enough. Perhaps, as one vendor suggested to me, it would be too embarrassing for a victim to admit, and so it remains secret. Or perhaps this isnt a real world problem. Yet. I look at this solution to a non-problem and I see an opportunity to preempt a problem that could arise. The way problems creep up in this business its only too easy to imagine some protocol-level weakness or some mail server vulnerability cropping up and suddenly everybodys got to patch or implement TLS in a hurry. Why not lock this door before someone walks in? TLS may be a solution in search of a problem, but on the Internet thats not always a bad thing. Security Center Editor Larry Seltzer has worked in and written about the computer industry since 1983. More from Larry Seltzer Check out eWEEK.coms for the latest security news, reviews and analysis. And for insights on security coverage around the Web, take a look at Security Center Editor Larry Seltzers Weblog.
Larry Seltzer has been writing software for and English about computers ever since—,much to his own amazement—,he graduated from the University of Pennsylvania in 1983.

He was one of the authors of NPL and NPL-R, fourth-generation languages for microcomputers by the now-defunct DeskTop Software Corporation. (Larry is sad to find absolutely no hits on any of these +products on Google.) His work at Desktop Software included programming the UCSD p-System, a virtual machine-based operating system with portable binaries that pre-dated Java by more than 10 years.

For several years, he wrote corporate software for Mathematica Policy Research (they're still in business!) and Chase Econometrics (not so lucky) before being forcibly thrown into the consulting market. He bummed around the Philadelphia consulting and contract-programming scenes for a year or two before taking a job at NSTL (National Software Testing Labs) developing product tests and managing contract testing for the computer industry, governments and publication.

In 1991 Larry moved to Massachusetts to become Technical Director of PC Week Labs (now eWeek Labs). He moved within Ziff Davis to New York in 1994 to run testing at Windows Sources. In 1995, he became Technical Director for Internet product testing at PC Magazine and stayed there till 1998.

Since then, he has been writing for numerous other publications, including Fortune Small Business, Windows 2000 Magazine (now Windows and .NET Magazine), ZDNet and Sam Whitmore's Media Survey.

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