Reverse IP Address Lookup: How to Trace IP Address to a Computer

Reverse IP address lookup is done with the help of the Address and Routing Parameter Area (arpa) special domain. IPv4 uses a reverse IN-ADDR entry in the in-addr.arpa domain, while IPv6 uses the ip6.arpa domain. The IP address is stored in reverse order. The zeros are not usually displayed in the IPv6 address, but are shown in the reverse IP address lookup. Reverse IP lookup is done using the pointer record. To trace an IP address to a computer in Windows, use the nslookup command; while in Linux, use the host command.

If a web server has many virtual hosts, it runs many domain names for the same IP address. WHOIS is a registry that gives information such as the domain name's owner and contact details such as address and telephone number. It also tells when the domain record was updated and when it expires. Traceroute is used in IP lookup to trace an IP address to a PC. It finds out the route taken by packets in an IP network. Ping determines whether a host is reachable across an IP network.

How to trace IP address to a computer using reverse lookup

The reverse IP address lookup is used in spam prevention, to block emails that don't come from valid domain names. You can also find out the domain name of the hacker, who is trying to break into your firewall. A DNS-based block list is a list of IP addresses of computers, which includes zombie computers, used to send spam to others. Two popular block lists are SpamCop and Spam and Open Relay Blocking System (SORBS).

IP address definition: An IP address is four numbers between 0 and 255 separated by periods. The IP address plays an important role in the TCP/IP network. Instead of typing the web address, you can type the IP address in the address bar of your browser, and it will take you to the same web page.

The Domain Name System (DNS) converts domain names into IP addresses. The domain name is also called the hostname and is referred to as web address in everyday use. A domain name groups Internet users, even if they are located far away from each other. For example, all the bloggers using the same blog host, have the same domain name, even if they may be located in different countries. A name server keeps a database of domain names mapped to IP addresses. If one name server doesn't know the IP address of a domain name, it forwards the request to another name server. A name server can also appoint another name server to be responsible for its sub-domain.

For example, calendar.example.com is a sub-domain of example.com domain, and latter is a sub-domain of the com top-level domain (TLD). To identify the IP address of calendar.example.com, your preferred server first asks the root server for the name server of the com TLD. The name server of the com TLD then points to the name server of the example.com domain. The name server of the example.com domain, then points to the name server of the calendar.example.com sub-domain. In this manner, you get the IP address of calendar.example.com. The root servers are operated by companies such as VeriSign and Cogent Communications. The name server of the example.com domain may be operated by a web hosting company.

DNS also allows redirection to a web page based on keywords used on search engines. You can also search or locate an IP address to get the city, state, country, latitude and longitude associated with it. So, if a visitor is coming from a foreign country, he can get a version of the web site in his own language. DNS also recognizes the browser and the operating system of the visitor. You can also get the IP address of a sender of an email message. This is done using the Mail Exchanger or MX record. You can also verify whether an email account exists. For example, when registering with a web site, a user may supply a fake e-mail address. The tool checks whether the email account is real. To trace an IP address to a PC using the reverse IP address lookup is very easy, and can be done simply by going to a specific web site.