DNS Frog is a free service offering simple web forms to perform DNS and IP analyses. For now Reverse DNS, IP localization, Ping, Traceroute, Whois, MX and NS requests tools are available. All tools take an IP address or a hostname as input argument.
Use this tool if you want to know who owns a domain name or an IP address. Your request will be search in the Whois database and typically you will know: the Registrar, the Creation date, the Updated date, the Expiration date, the owner contact, the administrative contact, the technical contact and the billing contact.
You want to know if a host respond to Ping requests from this host. Enter an IP address or a hostname. This host will try to send 3 ICMP packets to the host you entered. The results show you some statistics: how many packets have been received, how many have been lost and timing statistics.
This tool shows the route from this host to another host. It shows all intermediate hosts the packets are routed throw. IP addresses are resolved and timing are displayed.
This tool takes an IP address or a domain name as input argument. It tries to find mail exchanger records (MX records) for the given host.
For more details on MX records see the dedicated Wikipedia article.
This tool takes an IP address or a domain name as input argument. It tries to find Name Server records (NS records) for the given host.
If you are interested in Domain Name System you can find out more information on the Wikipedia article.