Tools
PTR lookup
See the hostname public DNS publishes for an IP address.
A PTR record is reverse DNS: the name that an IP address points back to. Mail servers often refuse mail when the sending IP has no PTR, or when the PTR does not match the mail host.
The address owner publishes the PTR, usually at the hosting or network provider. Changing an A record does not change the PTR.
PTR lookup FAQ
What is a PTR record?
The hostname stored for an IP address. Forward DNS goes from a name to an address. PTR goes the other way.
Why is reverse DNS empty?
The network that owns the address has not published a PTR. Ask that provider to set one.
Does this accept private addresses?
No. Only public IPv4 and IPv6 addresses are looked up.