Revision 0002
                                                              2020-12-06

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

However, many email services stealth filter their users and foolishly
delegate this filtering to remote blacklists. Blacklists operators
instruct them to reject messages that are sent from addresses and
domains present in their blacklists in such a fashion that the end users
are never aware of any blocking being done.

If you are using one of those email services, you may miss
correspondences without knowing it.

Services which use those blacklists contribute to the centralization and
destruction of the email ecosystem and enable the blacklist operators
from blackmailing ISPs and other services that do not comply with their
demands.

This results in many individuals and organizations that would have liked
to operate their own mail relay to rush for centralized services which
are often too large to be blacklisted or that have deals with the
blacklist operators.

When UDN is contacted by someone who uses an email address from one of
those services and that the reply is blocked, a notification that will
bypass the filtering to alert the user is sent.

The following is a list of email domains that are known to stealth
filter their users with third party blacklists and that are discouraged
from use:

protonmail.com/protonmail.ch
icloud.com
hotmail.com/outlook.com/msn.com/live.com
gmx.net/gmx.ch/gmx.de/mail.com
laposte.net
orange.fr
soverin.net

If you would like to contribute to the list, please send your report to
support@urdn.com.ua. We are especially interested in pseudo privacy
services that state principles of privacy and transparency and do not
really abide by them.