Domain name and Internet IP address translation is the backbone process of Internet communication. Forward and Reverse IP Address Lookup are the two principal terms involved in IP address lookup basics.
Two Types of Address Lookup Mechanisms in Internet Communication
Forward IP Address Lookup is a method for converting the domain name to an IP address. On the other hand, a Reverse IP Address Lookup involves converting the IP address to the domain name.
Internet Communication and the Domain Name System (DNS)
Web services usually support both Reverse IP Address Lookup and Forward IP Address Lookup for public addresses. The Domain Name System identifies a domain name and produces the related IP address for it. The two most essential services involved in this process are the Reverse DNS Lookup Service and the DNS Lookup Service.
The Third Type of IP Address Lookup – the Private
Private Local Area Networks (LANs) in organizations or educational institutions feature a third kind of address lookup mechanism, the private IP address lookup. Private networks connect with internal name servers, rather than relying on public DNS servers. Internal name servers, in conjunction with Windows Internet Naming Service (WINS), execute IP address lookup services on a private network.
Address Lookup Mechanisms in Use Prior to DNS Servers
Dynamic IP addressing was not always available with public networks. In the past, small business networks that did not have access to DNS servers maintained hosts files with lists containing pairs of IP addresses and computer names. IP addresses were looked up by referring to the hosts’ file. The hosts’ file is still in use by computer networks in specific scenarios, summarized below.
- Some of the UNIX-based computer network systems.
- Home networks with a router, which rely on static addressing, as opposed to DHCP addressing.
Other Forms of Address Lookup Mechanisms
Besides the DNS lookup mechanism for public addresses and the hosts’ file on private networks, a few other programs are also available for address lookups on private and public networks:
- The Network Operating System (NOS) of the computer contains utility programs to allow IP address lookups on the wider public Internet or a private LAN.
- Windows-based systems also support the nslookup command which is available to retrieve information from the hosts file and the name servers.