What is Reverse DNS?

What is Reverse DNS?

Reverse DNS (R-DNS) is a method of resolving an IP address into its corresponding domain name, which is the opposite of the common forward DNS lookup, which resolves domain names into IP addresses....

What is Reverse DNS Lookup Used For?

Block spam emails: Many email servers use reverse DNS to stop spam emails from IP addresses that do not have the proper website address (domain name) linked to them. The reverse DNS alone cannot fully block spam since some real email servers may not have the reverse DNS set up correctly. Analytics: Reverse DNS helps show website addresses instead of just IP address numbers in analytics reports, which is easier to understand. Track website visitors: The IP addresses of people visiting a website are recorded. Reverse DNS can find the website addresses for those IP addresses, helping understand where website visitors are coming from. This is useful for businesses trying to get new customers. Prevent network issues: Reverse DNS stops problems with some internet systems and protocols that need IP addresses to be properly linked to website addresses. Security: Reverse DNS can find the website address hosting a particular IP address. This information helps identify potential security risks on that server....

How Does Reverse DNS Lookup Work?

Reverse DNS lookup works by checking special records called PTR records. The PTR record connects the IP address with the domain name. Then, for the PTR record, a reverse record of the IP address would be 98.94.25.198 followed by adding.in-addr.arpa at the end: thus, it is the 98.93.15.198.in-addr.arpa:. So the PTR record points to the appropriate domain name of that IP address. The reverse DNS check is if the information about the PTR record matching the IP address exists in the DNS servers. If a PTR record exists it can find the domain name linked to that IP address. If no PTR record exists the reverse lookup fails. It is a good idea to have the PTR record set up especially if you are running the email server. This will helps other email servers trust that your emails are not the spam. The following image will show the difference between a regular DNS lookup (finding the IP from the domain name) and then a reverse DNS lookup (finding the domain name from the IP)....

Conclusion

Reverse DNS is the method that used to determine the domain name that is bound to the certain IP address. It does this by reviewing the unique PTR records in the DNS system. If a PTR record exists for a specific IP address, it would show the domain name within that IP. Proper setup of reverse DNS entries is highly recommended for email servers to avoid having outbound emails tagged as junk. Although not actively enforced, having reverse additional DNS records set is widely regarded as a best practice as it contributes to making the internet run more smoothly and ensures a secure digital environment....

Frequently Asked Questions on Reverse DNS – FAQ

What happens when visit a website by typing the IP address instead of the domain name?...