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.