IP Lookup: IP Address Location and Reverse IP (DNS) Lookup

IP Lookup: Find the Location and the Host Name of an IP Address

Enter an IPv4 or an IPv6 address and get three things at once: where the address is (continent, country, city, latitude, longitude and timezone), whose network it is (ASN and organization) and which host name it has (a reverse IP lookup, also called a reverse DNS lookup). If you leave the field as it is, the tool shows the data of your own address. The result is shown on the page; nothing has to be installed.

What you get

• Location. Continent, country with its flag, city, coordinates and timezone, taken from the GeoLite2 City database of MaxMind. The data is approximate: it points to the area of the network, not to a house.
• Network. The autonomous system (ASN) that announces the address and the organization behind it: a provider, a hosting company or a company network. It shows at once whether the address belongs to a home connection or to a data center.
• Host name. The name that the owner of the address has written in the PTR record of the reverse DNS zone, for example the name of a server or of a provider's customer line. The row is shown only if such a record exists.

What is a reverse IP lookup

An ordinary DNS lookup turns a name into an address. A reverse lookup does the opposite: it asks DNS which name belongs to an address. For this the address is written backwards under the special zone in-addr.arpa (IPv4) or ip6.arpa (IPv6), and the answer is a PTR record. Mail servers use it to check a sender, and administrators use it to read the logs and to find out whose server an address is.

Please note that this is not the list of all sites hosted on an IP address. The PTR record holds one name, which is set by the owner of the address and often has nothing to do with the sites on the server. Many addresses have no PTR record at all; then only the location is shown.

Why the location can be wrong

• An IP address does not carry a position. The database matches ranges of addresses with the places where the provider says they are used.
• Mobile networks, corporate networks, proxies and VPNs show the place of the exit point, not of the person. After you connect to a VPN, enter your address here to see in which country the VPN server is.
• A city is less reliable than a country. Some addresses have only a country or only a continent in the database.

Questions from the network engineers

What does no ip domain-lookup do? It is a command of Cisco IOS. By default a router tries to resolve a mistyped command as a host name and waits for a DNS answer, so the console hangs for a while. no ip domain-lookup turns this off. It has nothing to do with this tool, which checks addresses from outside, but it is one of the most searched commands about IP and DNS.

Related tools

To see all DNS records and the SSL certificate of a domain use the DNS lookup (it also answers the question which IP addresses a domain has), to read the registration data of a domain or of an IP network the Whois lookup, and to see whether a server answers the ping test.