My Turn: Blacklists are valuable in the continuing fight against spam

Posted: Sunday, March 02, 2003

If you are like me, you hate spam. You know, spam - those junk e-mails that fill up your inbox. I get dozens of them every day, from the scores of annoying "Refinance Your Home Now!" offers to the extremely vulgar "Hot Teen Sex!" advertisements for porn sites.

I have to spend a part of my day every day hitting DELETE-DELETE-DELETE on my keyboard. It's really frustrating. I have better things to do with my time, and I know my employer would prefer I be spending that time actually doing something productive.

That's why the Juneau Empire has joined a growing number of organizations that are taking a radical approach to fighting spam.

We've subscribed to a blacklist. And if your Internet service provider (ISP) is on that blacklist, well, that's too bad. We won't accept e-mails from you.

A blacklist is a database of ISPs that are either known spammers, or who have not taken suitable precautions to keep spammers from using their networks. These blacklists are maintained by independent organizations, and offered to anyone who wants to use them.

Businesses like the Juneau Empire subscribe to these lists to fight the ever-increasing tide of spam. Our e-mail server automatically compares every e-mail that comes in against the blacklist. If an e-mail is coming from an Internet address that is listed on the blacklist, it automatically gets kicked back to the sender.

And you know what? Blacklists work!

In the weeks since we implemented blacklisting, we've seen a substantial drop in the amount of spam we get - about a 50 percent reduction in the past month.

This system works so effectively because the Internet is a voluntary network of computer connections. There's no law that says my computer is obligated to accept e-mail from yours. You want me to accept your e-mails? Then keep off the blacklists.

Unfortunately, in this fight against spam, there are occasional innocent victims. Legitimate e-mails do get blocked sometimes.

A case like this happened recently. A customer of one of the big local ISPs (I won't name names, but they go by a well-known three-letter abbreviation) called us to let us know that their e-mails to the Juneau Empire were getting kicked back, blocked by our system. I investigated the matter, and sure enough, it turned out that one of that company's local e-mail relays was listed on a blacklist we use.

But what's more, we discovered that the other big three-letter ISP in town (again, not naming names) was also using the same blacklist. So not only could the poor customer not send e-mail to us, but they also could not send e-mails to anyone on that other big ISP in town.

An open relay is an e-mail server that allows anyone not on the local system to anonymously send e-mail from it. Spammers love them, because they can use them to send out huge amounts of spam without any accountability. According to some industry estimates, half of all the spam you get every day originated at an open relay. Spammers spend a lot of time and effort looking for these open relays.

There is no legitimate business or technical reason for any ISP to have open relays. But, sometimes ISPs get careless, or inexperienced techs accidentally leave them open, and when they do, spammers have a field day.

That's why blacklists exist. When an ISP is being irresponsible, leaving their system vulnerable to the spammers, they get blacklisted. This puts a lot of pressure on them to put their house in order, or they will start to lose customers.

In this case, I called tech support at the blacklisted ISP and told them what had happened, and they took immediate steps to get off the blacklist. It turned out that they had accidentally left a relay open, and as soon as they closed it, they got off the blacklist.

Problem solved.

Despite the temporary inconvenience to the customers of that ISP, the blacklist system proved that it works perfectly. An avenue that spammers use was closed, and I don't have to waste time with as many e-mails that tell me I can "Increase Your Breast Size Naturally!"

Kevyn Jacobs is the New Media director for the Juneau Empire, and a die-hard spam-hater. He can be reached at, unless you are sending him spam.

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