Enter an IP address to find out which hostname is set as its reverse DNS entry (PTR record).
Works for IPv4 and IPv6 addresses worldwide.
Here you'll find answers to the most common questions about our free reverse DNS tool.
Reverse DNS inverts normal DNS resolution: instead of determining an IP address from a domain name, it looks up the hostname associated with an IP address. This entry is called a PTR record (pointer record).
Reverse DNS is often used to check the trustworthiness of mail servers – many email providers won't accept messages from servers without a matching PTR record at all, or flag them as suspected spam. Reverse DNS also helps with network diagnostics and log analysis by making it easier to identify IP addresses.
A PTR record must be actively set by the owner of the relevant IP address range – usually the internet provider or hosting provider. With typical residential connections, it's often missing entirely or just points to a generic hostname of the provider.
Yes, for vServers and dedicated servers from Speed-Net, you can have the reverse DNS entry customized through the customer portal. Please contact our support team, who will be happy to help you set it up.
Yes, the tool is available to you free of charge and without registration at any time, and you can use it as often as you like.
Forward DNS resolves a domain name into an IP address, for example speed-net.ch into a specific IP address. Reverse DNS works the other way around and returns the hostname associated with a given IP address. Both directions are configured independently and don't have to match.
If you send emails from your own server, it's worth checking regularly, since a missing or mismatched PTR record can noticeably hurt deliverability. You should also review the record shortly after an IP change or server move and adjust it if needed.
No, that's not required. For email deliverability it's usually enough for the PTR record to point to a valid hostname reachable from the server – a technical name like mail.example.ch instead of the actual company domain is common practice.