nybo.w21.org: private mail server for w21.org
              85.215.152.252
              also mail.w21.org, mx0.w21.org
              SPF, DKIM, DMARC implemented
operator:     Jürgen Nickelsen
residence:    Berlin, DE
email:        postmaster@w21.org, nickelsen@mm.st
phone:        +49.178.6860628
Signal:       @jyrgenn.31
Threema:      ZZ2JK2ZM