What Is Reverse DNS?
A PTR record maps an IP address back to a hostname. Many mail servers reject email from IPs without a matching PTR record.
Setting a PTR Record
- Go to Servers → [Your Server] → Settings.
- Under Reverse DNS, enter your desired hostname, e.g.
mail.example.com. - Click Save.
Changes propagate within 5–15 minutes.
Verifying the PTR Record
>_BASH
$# Linux / macOS$dig -x <YOUR_IP> +short$$# Windows$nslookup <YOUR_IP>Expected output: mail.example.com.
Requirements
- The hostname must have a forward DNS A record pointing to the same IP.
- PTR records are per-IP; each IP can have one PTR record.
Email Deliverability Checklist
| Check | Tool |
|---|---|
| PTR record set | dig -x <IP> |
| SPF record | dig TXT example.com |
| DKIM configured | Mail server logs |
| Not on blocklists | MXToolbox |