2013-10-24



Suddenly, my mail server was blacklisted. Eek! That's no fun.

At least, I don't provide mail services for many people, but I do
host mail accounts of friends and some mailing lists.

Finding the source of the problem was  easy.  The  mailer  daemon
messages explained it clearly:

     554-gmx.net (mxgmx007) Nemesis ESMTP Service not available
     554-No SMTP service
     554-IP address is black listed.
     554 For explanation visit [...some website...]

(This is a reason why clear text  protocols  and  human  readable
status comments are good.)

First, I checked some blacklist query services [0] [1] *where* my
server  is blacklisted. The result was quite comforting: Only two
times blacklisted. One blacklist lacked further information,  the
other  had  the  whole  IP  listed, already since two years. Both
lists were of minior importance. This couldn't be the problem.

I discovered, that only GMX, Web.de, and some institution refused
to accept my messages. It smelled much like an internal blacklist
of United Internet. Hence, I wrote to their support team for  ex-
planation.

Many of the subscribers of the mailinglists I host have  GMX  and
Web.de addresses; this might have caused a classification as pos-
sible spammer.

The support reaction time wasn't in the business  range,  but  my
server  was  delisted about 15 hours later, at least. Sadly, they
told my only that they removed me from their blacklist,  but  not
why I became listed in the first run:

     We apologize for any inconvenience  caused  by  sending
     emails to our customers.

     In the meanwhile the IP address was de-listed from  our
     blacklists.

     The delivery of the emails should work normally again.

[0]  http://whatismyipaddress.com/blacklist-check
[1]  http://blacklistalert.org/


http://marmaro.de/lue/        markus schnalke <meillo@marmaro.de>