What Is a PTR Record (Reverse DNS) and Why Does It Matter for Email Deliverability?

A PTR record, also called a reverse DNS record, links an IP address back to a hostname. It works in the opposite direction of a normal A record, which points a hostname to an IP address. For email, it's one of the checks a receiving mail server runs to decide whether a message looks legitimate. If your emails are landing in spam and you've already checked your SPF and DKIM records, a missing or mismatched PTR record is often the next thing to look at.

What a PTR Record Does

When your mail server sends a message, the receiving server can look up the sending IP address and ask: "what hostname does this IP claim to belong to?" That answer comes from the PTR record. Many mail providers, including large ones like Gmail and Outlook, expect that hostname to exist and to reasonably match the domain the email claims to come from. No PTR record, or one that doesn't resolve properly, is treated as a red flag.

Why It Affects Whether Your Email Gets Delivered

A missing or broken PTR record doesn't always cause an outright rejection, but it raises the spam score a receiving server assigns to your message. Combined with other missing checks, such as SPF or DKIM, it can be enough to push a legitimate email into the recipient's spam folder instead of their inbox.

Unlike SPF, DKIM, or DMARC, a PTR record isn't something you add in your own domain's DNS zone. It's tied to the IP address itself, which means it's controlled by whoever owns that IP, typically your hosting provider.

How to Check Your PTR Record

1. Find the IP address your mail server sends from. You can find your hosting server's IP address from your control panel dashboard.
2. Use an online reverse DNS lookup tool. Enter your server's IP address and run the Reverse Lookup (sometimes labelled PTR Lookup).
3. Alternatively, from a command line on Windows, macOS, or Linux, run nslookup {your-server-ip} (or dig -x {your-server-ip} on macOS/Linux) and check the hostname it returns.
4. Compare the hostname you get back to what you'd expect, usually your mail server's hostname (something like mail.yourdomain.com or your host's server hostname). If nothing comes back, or the hostname looks unrelated to your mail server, the PTR record is likely missing or misconfigured.

What to Do If It's Missing or Doesn't Match

If you're on shared hosting

On shared hosting, your mail server's IP address is shared with other customers on the same server, and the PTR record for that IP is managed entirely by your host. You can't edit it yourself through your control panel's DNS zone editor. If a check shows it's missing or wrong, contact your host's support with the IP address and the hostname you expect it to resolve to, and ask them to correct it.

If you run your own mail server on a VPS or dedicated IP

Only the party that allocated the IP address can set its PTR record, so you'll need to request the change from whoever assigned you that IP, even though the domain itself is yours. Provide them with the exact hostname you want the IP to resolve to.

PTR record changes can take some time to take effect, similar to other DNS changes. A PTR record on its own won't fix deliverability if SPF, DKIM, and DMARC aren't also set up correctly. Treat it as one part of a complete setup, not a standalone fix.

If you haven't already set up SPF and DKIM for your domain, see How to Set Up SPF and DKIM Records to Stop Your Emails Going to Spam.