Free and Open Port 25 Use Is Doomed

By Larry Seltzer  |  Posted 2004-06-14 Print this article Print

It's a shame in a way and it will inconvenience many legitimate users. But it's inevitable: Rules for using port 25 will be tightened up by ISPs and eventually authentication will make the rules global.

Its hard to blame Comcast for beginning, as the Washington Post reported, to block port 25 on systems on their network that appear to be spammers. Everyone knows that a huge amount of spam is sent through broadband client systems that have been taken over—through backdoors—by spammers—zombied—and nobody has more broadband clients than Comcast.

While this move costs money and is potentially troublesome for Comcast, slowing down spam is not the only upside to doing this. The article claims that the change has brought about a 20 percent reduction in spam. Assuming that means 20 percent of the spam coming into Comcasts system, thats a lot of freed-up bandwidth.

Since spam makes up at least 50 percent of all e-mail, a 20 percent reduction in spam translates into a more than 10 percent reduction of overall mail, increasing the quality and reliability of that e-mail. And of course its an improvement for even those of us not using Comcasts network because a lot of those zombies send spam to us.

Im no big fan of Comcast, being a victim of their cable TV service, but their cable modem service is probably the best broadband deal for most people who have it available. I have to admire any steps they take to improve it, and this one isnt an easy decision. Comcast isnt typically a bunch of fascists when it comes to enforcing their rules. Its a violation of your Comcast agreement, for example, to run a mail server, but they havent been going around enforcing those rules. So I dont assume that they will suddenly swing over to abusive enforcement.

Within a couple years there will be widespread adoption of one of the emerging standards for SMTP authentication, perhaps the MARID specification currently under development by an IETF group. This will help to prevent spam from getting through to recipient mail servers, but its still going to be worth it for ISPs like Comcast to try to block spamming systems. If they dont, the mail still goes out and burdens the recipient servers into having to block it as unauthenticated. Both approaches are useful for cleansing the Internet of spam.

Next page: After authentication ...

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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