Reverse DNS (PTR records) for your IP

Reverse DNS (or rDNS) is the lookup that goes backwards from an IP address to a hostname. The record type that makes this work is called a PTR record. It matters most for outbound email deliverability — mail servers receiving your email use rDNS as one signal of whether the sending IP is legitimate.

Why rDNS matters

When your server sends an email to [email protected], the receiving mail server looks at the connecting IP and asks: "what is this IP's hostname?" The answer comes from a PTR record. Receiving servers compare that hostname against:

• The HELO/EHLO hostname your server announces. If they don't match, that's a deliverability red flag.
• The forward DNS of the rDNS hostname. If the PTR says mail.yourdomain.com, the receiver expects mail.yourdomain.com's A record to point back to the same IP. This is "forward-confirmed reverse DNS" (FCrDNS) and is required by many large mail providers (Gmail, Outlook.com).

If rDNS is missing, generic, or doesn't match, your outbound mail is more likely to be filtered to spam or rejected outright. Setting it correctly is one of the cheapest, biggest wins for email deliverability from your own server.

How to request rDNS for your IP

rDNS is set at the network level, not in cPanel or the DNS zone for your domain. We configure it on the upstream side, so you need to open a support ticket with the following information:

1. The IP address you want rDNS set for (your server's main IP, or a specific dedicated IP you've added).
2. The hostname you want it to resolve to (e.g. mail.yourdomain.com or yourdomain.com).
3. Confirm you've already set the matching A record in your domain's DNS (e.g. mail.yourdomain.com A → the same IP). Without the matching forward record, FCrDNS won't validate and the rDNS provides little value.

We'll set it within a business day or so. Propagation is fast — usually under an hour. Test with:

dig -x YOUR_IP +short

Common rDNS hostnames

Match the hostname to what your server actually announces in HELO/EHLO. Standard choices:

• Single-domain server: yourdomain.com or mail.yourdomain.com.
• Multi-domain server (cPanel hosting clients): the server's hostname, e.g. server.youragency.com. For VPS / dedicated where the hostname is something like vps123.canspace.ca, you can request your own custom hostname be set both as the server's hostname (in WHM) and in rDNS.

If you have multiple IPs

Each IP has its own PTR record and can resolve to a different hostname. This is useful if you host different domains on different IPs and want each domain's outbound mail to come from an IP whose rDNS matches. List all the IP/hostname pairs you want set in your support ticket.

What about IPv6?

The same applies for IPv6 addresses. PTR records exist for IPv6 too (in the ip6.arpa zone). If you're sending mail over IPv6, request IPv6 rDNS in the same ticket along with the v6 address.

Related articles

• Set up SPF, DKIM, and DMARC for your domain
• Understanding email bounce messages
• Getting started with your VPS or dedicated server

Still stuck? Open a support ticket