The server behind mail.alien8.de is a non-commercial privately run SMTP server. It's been used as the MX for a hand full of different domains.
Even though we only operate this server for our very own e-mails, be assured we hold the highest bar for security, operations and use most of the free mechanisms to deliver and filter e-mails.
All domains use SPF, DKIM, DMARC, DNSBL, TLS (Let's Encrypt),FCrDNS for the MX record, rate limiting, SPAM-filter etc. Further, we block IPs that do not act according to the SMTP profile or run brute force attacks on any part of the mail.alien8.de system.
Still, if there is any problem please do not hesitate to reach out by contacting us under postmaster@alien8.de via e-mail.