Revision 0004
                                                              2021-06-14
                                                              yyyy-mm-dd


Some email vendors foolishly delegate their filtering decisions to third
parties. In most cases the filtering is done in such a fashion that the
end-user is never aware of any filtering being done.

When these blacklists are used by centralized email vendors that have
million of users, the operators of the blacklists are offered great deal
of bullying powers which they can use to terrorize Internet companies.

Many Internet companies will systematically comply with the blacklisters
demands in fear of being blacklisted.

UDN operates its own email infrastructure and does not delegate its
filtering decisions to third parties.

The following is a list of email services and their domains that are
known for delegating their filtering decisions to third party
blacklisters. If you are a user of one them, you may not receive emails
from us and others without ever knowing about it.

  icloud.com
  hotmail.com/outlook.com/msn.com/live.com
      ^
       Use so much garbage that it's practically impossible to send
       anything to their users without being blocked for whatever
       reason.
  gmx.net/gmx.ch/gmx.de/mail.com
  laposte.net
  orange.fr
  soverin.net
  protonmail.com/protonmail.ch
      ^
       You didn't expect it? Well, here we're not surprised.

If you send us a message through the above services and wonder why we
are not responding, from now on you know as to why.

If you are aware of more known email vendors that rely on stealh
censorship, feel free to contact us to contribute to the list.