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Tag: filtering

January 2015 – The Month in Email

It’s February already! January went fast, right? At WttW, we are gearing up for MAAWG SF later this month — will we see you there? We started the year with a set of predictions about email. Mostly we think email will continue to be great at some things and not-so-great at other things, and we’ll […]

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Email filtering: not going away.

I don’t do a whole lot of filtering of comments here. There are a couple people who are moderated, but generally if the comments contribute to a discussion they get to be posted. I do get the occasional angry or incoherent comment. And sometimes I get a comment that is triggers me to write an entire […]

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AHBL Wildcards the Internet

AHBL (Abusive Host Blocking List) is a DNSBL (Domain Name Service Blacklist) that has been available since 2003 and is used by administrators to crowd-source spam sources, open proxies, and open relays.  By collecting the data into a single list, an email system can check this blacklist to determine if a message should be accepted […]

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URL reputation and shorteners

A bit of  a throwback post from Steve a few years ago. The problem has gotten a little better as some shortening companies are actually disabling spammed URLs, and blocking URLs with problematic content. I still don’t recommend using a public URL shortener in email messages, though. Any time you put a URL in mail […]

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The long tail of domains

I frequently get clients telling me that they have about 15 (20, 30) major domains on their list, and then a long tail of domains with only a couple of recipients. If you sort simply by the left hand side of the @, that’s true. When you’re sending email, it’s not just the domain in […]

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Superstition, correlation and reality

I’m not a huge baseball fan, probably a side effect of growing up in a city with no MLB team. But I do enjoy the social aspects of rooting for local teams when they’re winning big games. Last night I was following the World Series score online and switched over to watch the last inning. […]

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Content based filtering

Content filtering is often hard to explain to people, and I’m not sure I’ve yet come up with a good way to explain it. A lot of people think content reputation is about specific words in the message. The traditional content explanation is that words like “Free” or too many exclamation points in the subject line are […]

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Typo traps

People make all sorts of claims about typo traps. One claim that showed up recently was that Spamhaus has just started using typo traps. I asked my Facebook network when people started using typos to detect incoming spam. Two different colleagues mentioned using typos, both on the left hand side and the right hand side, […]

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Don’t wait to address delivery problems

One of the worst ways to deal with blocking issues is to ignore them and hope your mail magically moves from the bulk folder back into the inbox. While this does happen as ISPs and filter companies update their filters, it’s not that common and it’s usually the result of a sender actually cleaning up […]

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Incorrect rejection messages

At least one ESP and Spamhaus are currently investigating bounce messages at a couple ISPs incorrectly pointing to Spamhaus as the reason for the block. The bounce messages are taking the form: smtp; 554 p3plibsmtp03-07.prod.phx3.secureserver.net bizsmtp IB105. Connection refused. 192.0.2.24 is listed on the Exploits Block List (XBL) <http://www.spamhaus.org/query/ip/192.0.2.24> Please visit http://www.spamhaus.org/xbl/ for more information. […]

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