Every live Vpster instance has a dedicated IPv4. Reverse DNS, the PTR record, points that address at a hostname. Mail servers and some APIs check it. The record is edited on the instance, under Network.
Choose Change PTR, enter a hostname you control, and save. Leave the field blank to clear the record. The form asks you to confirm you control that name before you change it.
The console hostname and the PTR are different labels. Renaming the instance does not publish reverse DNS.
What the field accepts
The value is a hostname: letters, numbers, and hyphens, with at least one dot, up to 253 characters. mail.example.com fits. A bare word, an email address, and a URL do not.
The Network tab lists each address on the instance. The IPv4 row is the one most people set. If an IPv6 address is present, it has its own row. Many boxes show IPv4 only.
After you save
The console can show the new value before public resolvers do. Check from outside the server, with a DNS lookup, before you treat mail or an allow-list as done. A failed lookup in the first minutes is the lag, not proof the form was ignored.
PTR does not move the server to another city and does not change the IPv4. City stock at deploy is a separate note: Live IPv4 stock. The address itself is covered on Network.
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