Perbincangan pasal bind 9

The Domain Name System, or DNS, is one of the Internet's fundamental building blocks. It is the global, hierarchical, and distributed host information database that's responsible for translating names into addresses and vice versa, routing mail to its proper destination, and many other services.

(Another fundamental building block of the Internet is BGP routing, the routing protocol used to exchange routing information across the Internet. It is discussed in depth on our companion website about BGP4).

To understand what DNS does, let's take this small example. You'd like to visit a website, www.example.com.

After entering the website location, the browser has to find out the IP address of the host www.example.com. Therefore it makes a query to the local DNS resolver, which in turn queries the local DNS server. The DNS server does some more work - quickly finds out the matching IP address - and returns this answer back to the resolver.

In DNS jargon, this lookup is called a query for the "A record". This record describes the relation between a hostname and the corresponding IP address in DNS.

Your web browser is now able to contact the host www.example.com using its IP address. Further information retrieval takes place using the HTTP protocol, which is not discussed here.

Of course, the complete DNS resolving process is slightly more complicated. But finding the corresponding IP address for a hostname -or vice versa- is one of the basic tasks of DNS. The DNS protocol however has a lot more features and applications. For a complete understanding of the workings of the Domain Name System, you're encouraged to visit the DNS links section on this website.

The original DNS protocol is described in RFC 1034 and RFC 1035.

* RFC 1034 - Introduces domain style names, their use for Internet mail and host address support, and the protocols and servers used to implement domain name facilities.
* RFC 1035 - Describes the details of the domain system and protocol, and assumes that the reader is familiar with the concepts discussed in a companion RFC 1034.