No reverse DNS (PTR), or it does not match

What it means

Normal DNS turns a name into an IP address: mail.yourdomain.com to 203.0.113.10. Reverse DNS does the opposite: it turns the IP address back into a name. This reverse record is called a PTR record.

Receivers check two things:

1. The IP has a PTR name, for example mail.yourdomain.com.
2. That name points back to the same IP. This round trip is called "forward-confirmed reverse DNS".

Why it matters

Real mail servers almost always have a proper reverse DNS. Infected home computers sending spam usually do not. Many receivers, including Gmail and Outlook, reject or heavily filter email from IPs without a valid PTR.

Does this concern you?

Only if you send from your own server (a VPS, a dedicated server, an office mail server). If you use Google Workspace, Microsoft 365 or an email service, they manage reverse DNS for you. If a test from them shows a problem, contact their support.

How to check

Send a test email from the home page. The Reverse DNS section shows the IP that sent your email, its PTR name, and whether that name points back to the same IP.

How to fix it

Important: who sets the PTR?

The PTR record is not set at your domain registrar or DNS provider. It belongs to whoever owns the IP address: your hosting company (OVH, Hetzner, DigitalOcean, AWS, Scaleway…) or your internet provider.

1. Choose a name for your server, such as mail.yourdomain.com.
2. Create an A record for that name at your DNS provider, pointing to your server's IP:

   mail.yourdomain.com  A  203.0.113.10

3. Set the PTR at your hosting company. Most have a "Reverse DNS" or "rDNS" field in the server or IP settings. Otherwise, open a support ticket.

   203.0.113.10  PTR  mail.yourdomain.com

4. Use the same name in your mail server. The name your server announces when it connects (the "HELO" name) should be the same mail.yourdomain.com.

If the PTR exists but does not match

The report says the IP has a name, but that name does not point back to it. Either:

• Add an A record for the existing PTR name, pointing to the IP, or
• Change the PTR at your host to a name that already points to this IP.

Avoid generic names

Names like 203-0-113-10.dynamic.isp.example or vps12345.host.example look like home or default connections. A clear name on your own domain is better.

IPv6

If your server also sends over IPv6, it needs its own PTR and AAAA record too. Gmail is especially strict about this.

Check that it is fixed

PTR changes usually take effect within a few hours. Send a new test email from the home page: the Reverse DNS section should show your name and confirm it points back to the same IP.