Ever since Comcast bought out Adelphia and my main email address was forced to change, I’ve been getting intermittent indications that emails sent to me are not getting through. So, I decided to run this issue to ground...and here’s what I found...a very dirty little secret:
1) Comcast, as an example, has nine active email servers...at least one of which is almost always on a spam blacklist somewhere.
2) When these email servers are placed on another ISP’s blacklist, email sent to me via that ISP will have a one in nine chance of getting through.
3) There are hundreds, perhaps thousands of companies involved in managing, blocking and providing info related to spam. Many ISPs employ a third party for spam blocking and blacklisting “servicesâ€.
4) Some of these 3rd party spam blocking and blacklisting “services†are really running a scam where they actively seek out and blacklist ISP’s email servers, then demand a fee (ransom) to have the offending ISP’s email server un-blocked.
5) The situation is very dynamic, with literally thousands of email servers being added to and taken away from thousands of other ISP’s blacklists every day.
6) If your ISP has been blacklisted as a spam enabler, it is probably not possible for you to do anything about it. These blacklisting “service†providers are not regulated, make up the rules as they go, and usually demand that a representative of the offending ISP contact them to initiate de-blacklisting actions (pay a fee).
7) Many of the larger ISP’s resolve this situation by disabling their blacklisted email server’s IP and setting up a new one. That’s one of the reasons why Comcast has nine email servers, and why the IP address for these servers changes occasionally.
8) If you happen to know your ISP’s email server IP address, you can use this website to determine if your email is being blocked by some anonymous third party and/or another ISP:
http://www.spamhaus.org/sbl/. It's not a complete or turn-key list of blocked servers, but will give an indication at least.