Glossary
PTR record
A PTR (pointer) record maps an IP address back to a hostname, the reverse of an A record. Mail servers use this reverse DNS lookup to check that a sending IP has a real, matching name before they trust its mail.
What Is PTR Record?
In short PTR records live in a special zone built from the reversed IP.
RFC 1035's example: 10.2.0.52 is looked up at 52.0.2.10.in-addr.arpa, and the PTR record there holds a hostname such as mail.example.com. Whoever controls the IP block controls that zone, so you set PTR records through your hosting provider or email provider, not in your domain's DNS.
Receivers check forward-confirmed reverse DNS: the hostname in the PTR record must resolve back to the same IP. Google's sender guidelines require this from all senders. Yahoo requires valid forward and reverse DNS from every sender and recommends meaningful, non-generic PTR records that reflect your domain.
PTR Record Example
Example: a team moves cold email to its own server at 198.51.100.7. Test messages to Gmail fail until the hosting company sets the PTR record to mail.example.com and the team adds an A record for mail.example.com pointing back to 198.51.100.7.
PTR Record in Practice
If you send through Google Workspace, Microsoft 365 or an email service provider, the provider owns the IPs and sets PTR records for you. You manage PTR yourself only when you run your own mail server on your own IP.
FAQ
What is a PTR record?
A DNS record that maps an IP address to a hostname. It is the reverse of an A record, which maps a hostname to an IP.
What is reverse DNS?
Looking up the hostname for an IP address. The query goes to a name built from the IP in reverse order under in-addr.arpa, so 10.2.0.52 is looked up at 52.0.2.10.in-addr.arpa.
Does Gmail require a PTR record?
Yes. Google's sender guidelines require the sending IP to have a PTR record whose hostname resolves back to the same IP. Yahoo asks all senders for valid forward and reverse DNS too.
Who sets the PTR record?
Whoever controls the IP address: your hosting provider, ISP or email provider. You can't set it in your own domain's DNS zone. If you send through Google Workspace or Microsoft 365, the provider handles it.
Do This in Ken
Do This in Ken
Delivery provisions Google and Microsoft mailboxes for you. Those providers own the sending IPs and set their reverse DNS, so there is no PTR record for you to manage.
- Module
- Delivery
- Open in Ken
- /features
The new Ken opens to the waiting list in batches.
Related
- GTM Glossary
Every GTM term, grouped by topic.
- MX record
- IP reputation
- SPF (Sender Policy Framework)
- Sender reputation
- CNAME record
- Ken
Sources
| Source | Checked |
|---|---|
| Google: Email sender guidelines | |
| Yahoo Sender Hub: Sender best practices | |
| RFC 1035: Domain Names, Implementation and Specification |
Changelog
- Page published.