Is rDNS the same as a PTR record?

Effectively yes. "rDNS" names the concept of resolving an IP address to a hostname; "PTR record" names the DNS record type that implements it.

Why does rDNS matter for email?

Many receiving mail servers check that a sending IP has a PTR record, and that the hostname it gives resolves back to the same address. An IP with no PTR, or one pointing at a generic provider hostname, looks less accountable and is treated with more suspicion.

Can I set my own PTR record?

Not directly. Reverse DNS lives in the zone belonging to whoever owns the IP block, so you ask your hosting provider and they set it. Only forward DNS is under your control.

Do I need a dedicated IP for custom rDNS?

Yes. A PTR record applies to the whole address, so on an IP shared between customers it would be meaningless. Every plan here includes a dedicated IPv4 address.

Can I have a different PTR for each of my domains?

Not on one IP address. A PTR belongs to an address, not a domain, so one server gets one reverse hostname. If you need several, you need several IP addresses.

Is rDNS enough for good deliverability on its own?

No. It removes one reason to distrust you rather than creating trust. SPF, DKIM, DMARC, a gradual volume ramp and a clean opt-in list all matter alongside it.

Forward-Confirmed reverse DNS: the receiving server resolves your IP to a hostname via the PTR record, then resolves that hostname back to an IP, and checks the two match. Passing it is a basic sign of a properly configured mail server.

Is Port 25 guaranteed on every plan, or just open?

Both, depending on the range, and the difference is worth knowing before you buy. Outbound Port 25 is open by default on all 16 plans — no ticket, no approval step. On NVMe VPS, Cloud VPS, Classic VPS and VDS it is written into the published plan specification. On it is open because of how the network is run rather than as a documented guarantee. In practice it behaves the same on all of them, but if your business stops when you cannot send, buy the range that puts it in writing.

Definition · Reverse DNS

What is rDNS?

Reverse DNS turns an IP address back into a hostname. Mail servers check it to see whether the machine sending them a message is who it claims to be — which is why an IP with no PTR record, or a generic one, is treated with suspicion.

In More Detail rDNS VPS

Lookups a receiving server makes

IP → hostname, then hostname → IP. Both must agree.

PTR record: the IP’s claimed name
A record: does that name point back?
HELO name matching both
You cannot set the PTR yourself

What is rDNS? The definition.

Reverse DNS, or rDNS, maps an IP address back to a hostname — the opposite direction to an ordinary DNS lookup, and it is stored in a record type called PTR. Forward DNS answers “what address does mail.example.com point to?”; reverse DNS answers “what name does 203.0.113.10 claim?”. Mail servers use it as a cheap identity check: they look up the PTR for the connecting address, then look that hostname up again and confirm it resolves back to the same IP. That round trip is called Forward-Confirmed reverse DNS, and passing it is one of the oldest signals that a sending machine is run by somebody taking responsibility for it.

rDNS and PTR are the same thing — rDNS is the concept, PTR the record type.
Direction: IP address → hostname, the reverse of a normal lookup.
FCrDNS: the check that the hostname resolves back to the same IP.
Who sets it: the owner of the IP block, which is your hosting provider.
One per IP address — not one per sending domain.
Needs a dedicated IP to be meaningful at all.

Related: rDNS VPS · Port 25 · rDNS · SMTP VPS · Which software to run

In More Detail

Why it cannot be faked

Your mail server introduces itself with a HELO greeting, and it can say whatever it likes — there is nothing stopping a spam machine claiming to be mail.yourbank.com. The PTR record is different: it lives in the DNS zone belonging to whoever owns the IP address block, so only that party can set it.

So when the greeting and the PTR agree, and the hostname resolves back to the same address, the receiving server learns something real: whoever controls that IP space vouched for the name. It is a weak signal on its own, and it is cheap to check, which is why practically everyone checks it.

Why you have to ask your provider

You control forward DNS for your own domain, so you can create mail.example.com pointing at your server whenever you like. Reverse DNS lives in a different zone — one derived from the IP address and delegated to whoever owns that address block.

That is your hosting provider. This is why every host sets PTR records on request rather than giving you a field in a control panel, and why a provider that will not do it is a genuine blocker for anyone sending mail.

One record per address, not per domain

A PTR record belongs to an IP, so a single server has one reverse hostname no matter how many domains it sends for. People sending for several brands from one machine ask about this constantly, and the answer disappoints them.

The usual approach is to pick one neutral hostname on your own infrastructure domain for the PTR and the HELO greeting, and let SPF, DKIM and DMARC carry the per-domain authentication. If you genuinely need separate reverse names, you need separate IP addresses.

What Is rDNS? — Questions

Port 25 open, dedicated IPv4, rDNS on request.

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