Revision 0017
                                                              2023-11-19
                                                              yyyy-mm-dd


Lots of Mailbox Providers have the tendency of foolishly entrusting
third parties to filter their users. 
The Mailbox Provider sets up a remote connection to a blacklist's
maintainer so that whenever an e-mail is received, the IP address and/or
the domain name of the sender are submitted to the blacklister. The
blacklister then informs the Mailbox Provider that the sender is
blacklisted, or not. If the sender is blacklisted, the Mailbox
Provider's relay will drop the message and never deliver it to the end
user.

Blacklisters will of course insist the message should be dropped, not
delivered in a Spam folder, thus ensuring that the end user is never
aware that any filtering has been done.

More controlled mailboxes means more power for the blacklister. This is
why blacklisters will actively campaign to enroll large Mailbox
Providers.

When a blacklister controls million of mailboxes they will use this
power as a leverage to cause damages to their victims. This works by
placing the IP address and/or the domain name of the victim in their
blacklist which then prevents the victim from sending messages to any
mailbox that is under the control of the blacklister.

Out of fear, most victims will cave in the demands of the extortionists.

Because any actual spammer will find no difficulty in dodging the
blacklist, blacklisters must rely on misinformation and fearmongering to
keep their grasp. Most blacklisters will turn into whitelisters,
effectively blacklisting the whole Internet and whitelisting only their
customers and Mailbox Providers that are too large to be targeted.

This results in making it impractical to run one's own relay; because of
which, most people will give up on the idea turn to centralized
services.

Here at UDN, we have always used our own Mail Relays and have no
intention of changing this. Of course, because we do not cave in the
demands of extortionists, some of the blacklisters do not like us.

We have had a particular interest in the "Spamhaus Project", a notorious
blacklister. This blacklister went very far to have us stop providing
service to a web site that was critical of them, we have since been
monitoring their business and investigating their operator as well as
providing material and support to their victims.

We also have a list of services that we know rely on blacklisters:

  icloud.com
  outlook.com (msn.com, live.com, hotmail.com, ..)
  gmx.net (gmx.ch, gmx.de, mail.com)
  laposte.net
  soverin.net
  mailfence.com
  protonmail.com, protonmail.ch /* this one behaves in sharp opposition
                                   to their official propaganda  */
  fastmail.com
  icloud.com

We recommend you do not use the above services, unfortunately the list
is non-exhaustive and many more of such providers exist. If you use one
of them to contact us, it is possible you will not receive a reply from
us; however, when this happens, our system will now ensure to bypass the
blockade and send you a notification to inform you of the problem.