Admin tip: set rDNS / PTR on a crypto VPS

Mail and some APIs want a PTR that matches the HELO. Ticket the hostname. You run Postfix.

Le corps de l'article est en anglais. L'interface, le catalogue et la caisse sont traduits.

Why PTR shows up in tickets

Receiving MTAs and a few payment APIs check reverse DNS. Postfix documentation will not save you if the PTR is a generic allocator name. This is the usual first ticket after someone buys a mail VPS with crypto.

What to send

1. The IPv4 (and IPv6 if you use it).
2. The FQDN you already pointed A/AAAA at.
3. Invoice code if the panel is new.

Then harden OpenSSH manual and keep port 25 for mail you actually operate. We do not run the MTA.