THE CHALLENGE/RESPONSE ANTISPAM SOLUTION
Finally, spam relief for $3/month!
By Doug Noble
UPDATE 10/18/2005: Mailblocks announced service discontinuation. Mailblocks was purchased some time ago by AOL and stopped accepting new subscribers over a year ago. Their development team apparently was moved onto developing the free AIM Mail instead, which does not appear to include challenge/response. I have looked into some alternatives and have found Spam Arrest as an alternative solution offering challenge/response. At $35/year a little more than Mailblocks was but a small price to pay for a spam free mailbox! I opened a SpamArrest account to protect my daughter's mailbox from being exposed to spam, and it has been extremely successful. I plan to write more in depth on SpamArrest and other spam blocking technologies soon.
Do you receive a ton of spam in your mailbox? I do, and it's a headache, especially since I do business on the web. Hundreds of spams bombard me each day with their annoying and often offensive messages. It's worse than the telemarketers who used to call me before I signed up for the Do Not Call List! In spite of having Symantec spam filtering software on our mail server, a lot still gets through, as spammers use creative messages and tricks to fool the rules our anti-spam vendor has setup. If we tighten the spam filter rules on the mail server then inevitably some legitimate mail gets deleted. I've tried writing my own rules for Microsoft Entourage and installed the Spamsieve Bayesian filter for Entourage but it needs to be trained to be effective. For a while I used Spamfire, a program for Mac OS X or 9 that runs locally and checks your email, then marks what it thinks is good and bad. But it is not infallible in detecting which mail is spam. And either way the spam ends up somewhere on your hard drive till you delete it.
A different solution is called "challenge/response". The idea behind it is, before you can send me an email the first time, you have to pass a test to prove you are an individual human, not a machine in China blasting out junk mail to millions. The first time you send me an email, you will get a personalized automated email back from the Mailblocks.com server saying something like "Sorry to bother you but I am overloaded with spam, so I request that you click the link below to prove you are a legitimate emailer".
The link takes you to a web page where you see an alphanumeric code in a
graphic. You simply type the code you see into a box. The challenge/response
system sees the answer and delivers your email to my Inbox. Most importantly
it learns your email address so next time, you will not get a challenge,
your email will go direct to my Inbox.
How does this stop spammers? Spam is not sent by individuals
typing one email and sending it. It is sent using computers loaded with
millions of email addresses which often use fake return addresses. They
are not capable of responding to every challenge email and reading that
code embedded in a graphic in a fancy font. So the challenge will go unanswered
and their email will sit in the "pending folder" for a few days till it
is dumped, never to be read by me.
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[Note: this information no longer current, Mailblocks service has been shut down, I now use SpamArrest] I am currently using Mailblocks.com I have forwarded email
accounts which get a lot of spam to my account on the Mailblocks server. In
the year since I started using the service over 50,000 spam emails have
been successfully diverted from my mailbox! The spam stays on the Mailblocks
server till it is deleted automatically after a predetermined time and never
reaches my hard drive. I can read my mail online using Mailblocks webmail,
which works OK in Safari and Internet Explorer for OS X but does not work
to login once in a while to see if any legitimate mail is sitting waiting
for a response to a challenge, but good mail gets through right away. I have
set some rules with keywords to set apart mail that is likely of interest,
such as "Filemaker" since that relates to my business. I check the "good" mail
in the Mailblocks Inbox using POP3 access using Entourage, Apple Mail or Outlook.
It's no harder to setup than any other ISP account.
I have not had any complaints from people sending
mail to me, the challenge is polite and easy to navigate and does not ask
them for personal information. But, to avoid challenging all your friends
or business associates, you can import your address book from Outlook or
Entourage into Mailblocks "white list". That mail will automatically go
direct to your Inbox. And I suggest you use a different, private address
for business mail where you initiate the correspondence, so that people
who you already know are not challenged when they reply!
The downside of challenge/response systems is
that they are only effective for mail sent to you by humans. For example
if you order a book from Amazon.com or book a rental car, the automated
computer acknowledgment that arrives in your mailbox will be challenged,
and Amazon's computer is not smart enough to respond to the challenge. (It
probably uses a "do not reply" mailbox that is never looked at). So that mail sits in the Mailblocks "Pending" folder till you check it. Listserv messages and broadcast newsletters are also going be be caught. You can add the "from" address to your whitelist but some lists use different addresses each time they send mail. The solution is to use a different email address for online orders, newsletter subscriptions etc. which is not routed through Mailblocks. For example get a free Yahoo email address, or ask your ISP for a second address. If you post to public forums, or post your email address on your website, you should also use a "throwaway" email address, as spammers comb the web for addresses to add to their lists. Keeping a "private" address
which you do not post publicly but use for correspondence with friends and
business contacts is a smart way to cut down on spam.
Initially I had a problem with emails showing
up in the Mailblocks Deleted folder as well as my Entourage Inbox. Mailblocks
tech support is not speedy, it took escalation to resolve, but it turned
out I had set my Entourage to "leave messages on server" and this caused
a conflict. Disabling that option solved the problem. In general Mailblocks
is easy to setup and use, so you probably won't need help. Overall I am
very happy with Mailblocks. The number of emails that reach my mailbox has
decreased dramatically and I now find the important ones quickly! Mailblocks recieved PC Magazine's
prestigious Editor's Choice. Mailblocks.com is just one of many players in this area. Others include spamarrest.com [which I now recommend in place of Mailblocks. Ed.] and ipermitmail.com which I have not tested, but appear to work in a similar manner. Earthlink offers challenge/response as part of its anti-spam solution to Earthlink subscribers. So if you are getting bogged down by spam, I recommend you look into this solution.
Copyright ©2004 Doug
Doug is the founder of MacTalent and owner of ADWEB Services Inc. a Miami Florida Web Design and Hosting company specializing in searchable websites based on the Filemaker database.