If outbound email from your server is landing in spam folders or getting rejected outright, a missing PTR record is one of the first things worth checking. It's a small DNS detail, but increasingly, mail providers treat it as a hard requirement rather than a nice-to-have.
What is a PTR record?
A PTR (Pointer) record does the reverse of what a regular A record does. Where an A record maps a domain name to an IP address, a PTR record maps an IP address back to a hostname. When a receiving mail server gets a connection from your server, it can perform a reverse DNS lookup on your sending IP to see what hostname it resolves to, then compare that against the hostname your server introduced itself with during the SMTP conversation.
| Record type | Maps | Who controls it |
|---|---|---|
| A record | Domain name to IP address | Domain owner, via DNS zone |
| PTR record | IP address to domain name | Owner of the IP address block (usually the hosting/network provider) |
This distinction matters: unlike most DNS records you manage for your domain, a PTR record lives in a separate reverse DNS zone tied to the IP address itself, not to your domain. That's why it's typically requested from your hosting provider rather than edited in your domain's own DNS zone.
Why PTR records matter for deliverability
- Spam filtering. A missing or mismatched PTR record is a strong signal to spam filters, since legitimate mail servers are expected to have one.
- Sender reputation. Major inbox providers factor rDNS into their overall assessment of whether your server is a trustworthy sender.
- Forward-Confirmed Reverse DNS (FCrDNS). This is when a sending IP's PTR record resolves to a hostname, and that hostname's own A record resolves back to the same IP — both directions matching. Several major mailbox providers now expect this alignment, particularly for servers sending in volume, and treat a mismatch or missing PTR as grounds to reject the connection rather than just flag it as suspicious.
PTR records work alongside — not instead of — SPF, DKIM, and DMARC. All of these signals contribute to whether a message reaches the inbox, and skipping any one of them weakens the others.
How to check your PTR record
- Command line. On most systems, a reverse lookup command (such as
nslookupordig -xfollowed by the IP address) will return the associated hostname if a PTR record exists, or an error if it doesn't. - Online DNS lookup tools. Many free tools let you paste in an IP address and see the PTR result without using a terminal.
- Your hosting provider. On a hosted or dedicated server, your provider manages the PTR record for your assigned IP and can confirm or update it on request.
Setting up or fixing a PTR record
- Contact your hosting or network provider. Since PTR records belong to the IP address owner, this isn't something you can add yourself through your domain's DNS zone. For Avalon-hosted servers, our support team handles this request.
- Give them the hostname you want it to resolve to — typically the same hostname your mail server uses to identify itself when connecting to other servers (for example,
mail.yourdomain.com). - Make sure that hostname has a matching A record pointing back to the same IP address, so both directions of the lookup line up (FCrDNS).
- If your server also sends over IPv6, ask for a PTR record in the IPv6 reverse zone as well — an IPv4-only PTR record won't cover IPv6-originated mail.
- Re-check after a few hours to confirm the change has propagated, and keep an eye on bounce rates and spam complaints afterward.
Common issues
- No PTR record at all. Common on IPs that haven't had one explicitly requested — ask your provider to add one for your sending hostname.
- PTR and A record don't match. The PTR resolves to a hostname whose own A record points somewhere else, breaking FCrDNS — align both so they agree.
- Shared IP address. Since a single IP can only have one PTR record, if you're on a shared sending IP with other customers, you may not be able to set a custom PTR yourself; a dedicated IP gives you full control over this.
- Change hasn't taken effect yet. DNS propagation can take a few hours, occasionally up to about two days — wait before assuming something's wrong.
FAQ
Can I set my own PTR record through my domain's DNS panel? No — it belongs to whoever owns the IP address, which for most hosting customers is the hosting provider, not the domain registrar.
Does every domain need a PTR record? Every server that sends outbound email needs one for its sending IP. If you send email exclusively through a third-party platform, that provider is responsible for their own sending IPs' PTR records.
What happens if my PTR record is missing? Depending on the receiving provider, your mail may be delayed, routed to spam, or rejected outright — increasingly the latter for higher-volume senders.
