Dealing with DPI

By Larry Seltzer  |  Posted 2009-04-24 Print this article Print


I don't see a whole lot of allowance in Harris' statement for the value of security functions carried out by the ISP. I see an ideological commitment to privacy that devalues functions that almost all customers want and that are provided completely in good faith. Unfortunately, it's Harris' agenda I hear influencing the committee. It's certainly not in fashion to defend the interests of ISPs. The best I see coming out of this is an onerous regulatory burden. The testimony essentially dismisses the value of DPI for "ongoing" security functions, including spam filtering, and asserts that there are better ways available, as if ISPs wouldn't use better ways if they could.

As Paul Ferguson of Trend Micro said on the matter, "DPI, in and of itself, isn't necessarily evil. It is how it is used which can bring up concerns." I was inclined to get all indignant about this, but Ferguson is right that there's an obvious logical ground on which to proceed.

The advertising functions bring revenue to ISPs, and it would be a mistake to ban them arbitrarily. The alternative for ISPs is to charge more for their subscriptions. If ISPs make such DPI functions opt-in and they disclose exactly what they are doing with the data, then I can't see a good reason to object. Why would anyone sign up for it? Perhaps they could make it worth your while, for instance by cutting a dollar or two off your monthly subscription fee. Maybe I wouldn't sign up for that, but I bet a lot of people would, and who are we to tell them they can't?

On the other hand, adopting an extremist view of DPI, like that of the CDT, in legislation would be a great victory for Internet malefactors everywhere. Defense in the network isn't perfect, but users need all the help they can get, and they're no good at protecting their own PCs.

It's also worth noting that ISPs are required under CALEA (the Communications Assistance for Law Enforcement Act) to maintain systems for performing DPI to service requests by law enforcement. There's even an IETF (Internet Engineering Task Force) specification for meeting CALEA requirements. The law says nothing about the capabilities being used only for law enforcement. So ISPs are required to have this capability.

Some people have such an irrational distrust of ISPs that they want them legally hamstrung, so they will be just dumb conduits for data, the electric companies of Internet data. Ironically, at the same time that we're talking about making the electric grid smarter, we're talking about making the Internet dumber. This is not a step forward.

Security Center Editor Larry Seltzer has worked in and written about the computer industry since 1983.

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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