On-Rev: Odin emails rejected due to poor reputation

[Mark Wieder]

Stewart-

Saturday, April 20, 2013, 9:08:58 AM, you wrote:

> I have a business account with Shaw and host my own email server
> for my business.  Every few months, I wonder why people are not
> getting my emails.  It turns out that Cloudmark has blacklisted my
> domain and email is going into people's Spam folders as a result.

I used to work at Cloudmark. Unless things have changed drastically
there, Cloudmark doesn't maintain blacklists. There are several
heuristics used to determine the spam blocking threshold, and the
blacklist approach is one of the least reliable brute force methods.
The most effective algorithm used by Cloudmark is crowdsourcing: when
a user reports a message as spam, both the email message and the user
get a reputation rating. If more users report the same message, then
the rating of the message and the user go up. If more users report the
message as a false positive, then the message's rating goes down, but
so does the original reporter's. If a message passes a given threshold
then it's declared spam unless further reports bring down its rating.
If you successfully report several spam messages then your reputation
goes up and further spam reports will carry more weight.

The blacklists are maintained by SpamHaus, SpamCop, SORBS, etc., and
if you find out which lists are blocking your domain (or worse, the ip
address or block of ip addresses of the server) then you can email the
appropriate parties to be taken off the blacklist. They usually
respond pretty quickly, but I have to say I've never liked the
blacklist approach.

-- 
-Mark Wieder
 mwieder at ahsoftware.net