DNS Server

The DNS system is the system, which powers the Internet as we know it today – it is responsible for turning domain names to IP addresses and locating them on one of the millions of hosting servers. But the DNS system would have been just a concept without its physical representation – the DNS server.

DNS servers are organized in a hierarchical order and communicate with each other through private network protocols. The master DNS servers, known as root servers, store the whole database of the Internet domain names and their corresponding IP addresses. They are owned by various independent agencies based in the United States, Japan, the UK and Sweden. The other lower-level DNS servers maintain only parts of the total database of the domains/addresses and are owned by businesses or ISPs (Internet Server Providers). A DNS server can be any computer registered in the DNS system, running special DNS software, which helps it resolve domain names to their appropriate hosts. Each DNS server features a public IP address and includes a database of network names/addresses of other Internet hosts.

How DNS server works

The communication between users' computers and DNS servers is initiated as soon as you type a website address (domain name) into a web browser. Then the browser, acting as a DNS client, sends an immediate request to your ISP's DNS server(s), which search for the matching IP address in its/their database.

If no match is found, the DNS server automatically passes the request to another lower-level DNS server or even to a root server, if necessary. As soon as the matching domain name and IP address are located - the request’s response is transmitted back to your browser through the DNS server network. This process is called forward DNS, as opposed to reverse DNS, where the DNS server takes major part as well.

Uses of Static IP

Some infrastructure situations have to use static addressing when finding the Domain Name System host that will translate domain names to IP addresses. Static addresses are also convenient, but not absolutely necessary, to locate servers inside an enterprise. An address obtained from a DNS server comes with a time to live, or caching time, after which it should be looked up to confirm that it has not changed. Even static IP addresses do change as a result of network administration.

In the real world, static IP address mappings in hosts may not have been maintained as systematically as are RR records in a DNS server. It is entirely possible that different host mapping entries for the same name point to different addresses.