Reverse DNS
Find PTR hostnames associated with any public IPv4 or IPv6 address.
What This Tool Does
Our reverse DNS lookup tool queries PTR records to find hostnames associated with an IP address. This is the opposite of a regular DNS lookup—rather than domain to IP, it resolves IP to hostname. Reverse DNS is useful for email validation, log analysis, and infrastructure investigation.
Common Use Cases
- Verify email server configuration (required for reliable email delivery)
- Identify the hostname of servers in network logs
- Debug network issues by identifying device names
- Check if reverse DNS is properly configured for your servers
- Investigate suspicious IP addresses in security logs
Frequently Asked Questions
Why is reverse DNS important for email?
Many email servers check that the sending IP's reverse DNS matches the sending domain. Missing or mismatched PTR records often cause emails to be marked as spam or rejected entirely. Proper rDNS configuration is essential for email deliverability.
Why doesn't my IP have a reverse DNS record?
PTR records must be set up by whoever controls the IP address—usually your ISP or hosting provider. Many residential ISPs don't configure reverse DNS by default. Contact your provider to request PTR record setup.
Can I set my own reverse DNS?
Only the owner of the IP address block can set PTR records. For most users, this means contacting your ISP or hosting provider. Cloud providers like AWS, Azure, and GCP allow you to configure reverse DNS through their control panels.