Guides PTR
What is reverse DNS (PTR)?
Normally you ask DNS: 'which IP address belongs to this name?'. Reverse DNS flips that: 'which name belongs to this IP address?'. That answer lives in a PTR record (pointer). For websites it usually doesn't matter, but for mail servers it does: a receiving server checks whether the IP address offering it mail has a proper name. If that name is missing or makes no sense, it counts against you. A correct reverse DNS is part of a well-configured mail server.
How it works
A PTR record links an IP address to a hostname, for example: the IP 192.0.2.44 points back to mail.example.com. Unlike regular records, you usually don't manage a PTR in your own domain's DNS, but through the party that owns the IP address, often your hosting or internet provider. So you have to request it.
Ideally it's 'forward-confirmed': the name points back to the same IP via an A record. Then the there-and-back path matches, and receivers trust that.
Why it matters for mail
Many receiving mail servers check the reverse DNS of the sending IP address. If the PTR record is missing, or contains a generic name (like a datacenter's), that's a serious mark against you: your mail is more likely to land in spam, and big receivers like Gmail now even require a valid PTR record and may flatly refuse your mail otherwise.
For websites this hardly plays a role. It's purely about mail servers that send mail themselves.
How to set it up
- Do you send mail via an external service (Google Workspace, Microsoft 365, a mail provider)? Then it handles reverse DNS, and you don't need to do anything.
- Run your own mail server? Ask the party that provides the IP address (hosting/provider) to set a PTR record pointing to your mail server's hostname.
- Make sure that hostname points back to the same IP via an A record ('forward-confirmed').
- Verify it's correct before going into production.
Frequently asked questions
Do I manage PTR in my own DNS?
Usually not. The PTR record belongs to the IP address, so the party that owns the IP (your hosting or provider) sets it. You request it from them.
Do I need reverse DNS for my website?
For a website it normally doesn't matter. It's mainly important for mail servers that send mail themselves.
What does 'forward-confirmed' mean?
That the there-and-back path matches: the IP points via PTR to a name, and that name points back to the same IP via an A record. Receivers trust that more.
My mail lands in spam. Could it be reverse DNS?
It can be a factor, especially with your own mail server without a (correct) PTR record. But also check SPF/DKIM/DMARC and blacklists. Usually it's a combination.