1. The Domain Name System (DNS) By Alex Kamau B101 Technology Context

2. contexts Introduction How does it work The size of DNS The Hierarchy The key components UK legislation of DNS Limitations of DNS Conclusion References

3. What is the Domain Name System? Definitions: “The Domain Name System (DNS) is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network” “DNS is a protocol within the set of standards for how computers exchange data on the Internet and on many private networks.” The Domain Name System basically translates simple easy to remember website names into complicated numeric identifiers in order to locate a website worldwide.

4. How does the domain name system work? The domain name is like an internet phone book, when you are looking for a certain website for example www.google.co.uk the DNS will translate those words into numeric identifiers in order to locate the website, in other words the DNS will simply translate the words into numbers which are assigned uniquely to every website which works just like a phone book, you type in the name of the person you are looking for and it will find the person and there unique phone number. www.google.co.uk

5. Currently the internet uses ipv4 which holds around 4.3 billion web addresses, and due to the increasing amount of websites the list is forever growing. For the simple function of turning words into ip addresses, the domain name system is now worth several billion pounds, this gives us an idea of how big the DNS is and is getting, with most countries in the world assigned a unique identifier like.ca for Canada and.ke for Kenya.

7. The DNS works in through a tree structured system where it starts at the top which is called the root and works its way down to find the website that you are looking for. The DNS acts like a pointer, it does the leg work to find out where the website is located on a server. For example if you are looking for www.facebook.com the DNS will read that and acknowledge that you are looking for a.com website which is located in the top level domain, the DNS will then go through the registry for.com to find where Facebook is stored in terms of the servers and it will the go into the found servers and query where Facebook is stored once found the website will then be displayed on your browser. www.facebook.com

8.  Name space Firstly we will look at the name space; DNS provides “a name lookup facility that is similar to a standard telephone directory. To perform lookups, DNS relies on a distributed system of name servers and a standardized language to query these server” The name space is where we find all the domains and computers found under the root directory. The name space has a hierarchal structure the root domain is at the top, the first level domain is where we find the.com and co.uk etc domains. Underneath the first level domain is where we find the second level domain which are registered to companies or users such as www.google.co.uk.www.google.co.uk For easy administration, domain names can be organised into zones. A zone is discrete and it is used to give different types of authority for different parts of the domain.

9.  The Name Servers Each zone has either a primary or a secondary name server, and the name server usually stores all the information about a zone. Data in a zone has to be stored on both the primary and secondary name servers, having data on both primary and secondary name servers reduces the work load on the primary name server when it comes to retrieving information. The name server listens for DNS inquires and if the queried name is in the local zone data or cache the DNS responds immediately with an answer. The secondary name servers always hold a copy of zone information from the primary name server from a set time.

10.  The Resolver The resolver acts like a wire between two devices where one is requesting a domains ip address and the other is holding the information. The resolver would be the one which returns the domains ip address to the device requesting it. The resolver is key because it maps the root which it will use to deliver the requested information.

11.  In the UK, having a trademark does not mean you can have a domain name associated with the trade mark. Often we see companies going to court due to domain names and to take legal action against anyone using the domain names associated with trade mark to damage reputations.  The UK law states that “domain names will be registered on a first come first severed basis” also, if someone else claims to have the right to the name by trade mark then they must contact the current owner with the correct trade mark documents and also where the domain name has been registered prior to the trade mark the domain name holder will continue to own it until a resolution is agreed.

12.  Security is one of the concerns when it comes to limitations. The internet can be a very interesting place but also dangerous. Due to the increase of people on the internet there are also people who want to corrupt this luxury we enjoy, the DNS is prone to attacks from hackers, also people stealing information from domains.  The DNS also has a maximum number of domains allowed. In the IPv4 the maximum is fast approaching, we are now starting to see devices like 4g mobile phones using IPv6 to counter this limitation and also with IPv6 there is a possibility of improvements.

13.  The creation of DNS has enabled people to surf the internet easily, even the most computer illiterate people can use the internet due to DNS, having the ability of just typing a string of keywords and a relevant webpage being displayed is amazing.  DNS has also helped companies grow massively with the increase of online shopping which can also be done internationally due to the fact that the top level domain includes domain names that end in.co.uk or.au for Australia enabling people to surf websites that are world wide.

14. References 1. Andrew Rossiter - 2009 – DNS hierarchy - http://www.whatsmydns.com/pic1.gif 2. Author unknown - 30 November 2011- Domain name system retrieved from - http://en.wikipedia.org/wiki/Domain_Name_System#Do main_name_registration 3. Kingsley Napley LLP.- accessed on 01/12/2011- domain name law retrieved from - http://www.weblaw.co.uk/domain-name- disputes/domain-name-law 4. Marshall Brain – July 29 2010 - How Domain Name Servers Work - http://www.howstuffworks.com/dns.htm 5. / 6. Tuxan – February 16 2009 -Configure and Use Dynamic DNS – retrieved from - http://www.codelathe.com/blog/index.php/2009/02/16/ configure-and-use-dynamic-dns/