How do I set up rDNS (PTR)?

If the left menu of the product details page has an rDNS entry, you can set PTR records there yourself.

Only the IPs listed on that page support it. If there is no entry, or the IP is not in the list, that IP does not support rDNS, and it cannot be set manually through a ticket either.

Before setting it, first add an A or AAAA record for the target domain pointing to that IP.

If you plan to run a mail server, also note the port 25 policy.