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[description], Story, any other text you want to use. Understanding DNS by: Clare Lawrence
How to understand the Domain Name System Ever wonder why DNS systems came into existence? Efficiency. Every computer has a distinct IP address, and the Internet needed an elite method for obtaining these addresses and for managing the system as a whole. Enter ICANN. The Internet Corporation for Assigned Names and Number manages the DNS root of the Internet domain namespace. ICANN's role is to manage the assignment of identifiers, ensuring that all users have unique names. The DNS system is run by a series of servers called DNS servers. ICANN manages the root DNS domains, under which are the top-level domains. It also manages:
Beneath the top-level domains are other naming authorities such as Nominet, the UK's naming authority. How does a DNS Query work? The process occurs in two parts. Firstly, a name query begins at a client computer and is passed to DNS client service for resolution. When the query cannot be resolved locally, DNS servers are queried. For example, when a web browser calls the fully qualified domain name www.discountdomainsuk.com, the request is passed on to the DNS client service to resolve the name by using locally cached information. If the query is held in the cache, then the process is complete. If, however, the query cannot be answered locally, the DNS client service uses a server list (ordered in sequence) to query external DNS servers. When a DNS server receives a query, it first checks to see if it is authoritive for that domain name. If it is authoritive, it resolves the name, and the process is complete. If the DNS server is unable to resolve the query, it in turns queries other DNS servers, using a process known as recursion. DNS servers make use of root hints to assist in locating DNS servers, which are able to provide the required result. In this way, DNS queries are minimised and the Internet is able to operate quickly and effectively. A typical query may run as follows: Client contacts Nameserver A looking for www.discountdomainsuk.com. Nameserver A checks its cache, but can't answer, so it queries a server authoritive for the Internet root. The root server responds with a referral to a server authoritive for the .com domains. NameserverA queries the the .com server and gets referred to the server authoritive for www.discountdomainsuk.com. Nameserver A queries this server and gets the IP address for www.discountdomainsuk.com. Nameserver A replies to the client with the IP address. Queries can return answers that are authoritive, positive, negative or referral in nature. In the event of a negative answer, another DNS server is queried. By Clare Lawrence 13th August 2004
web radio
If you are thinking about buying web radio online, here are a couple of things to remember to ensure safe online transactions. Before purchasing web radio make sure you are on a secure connection when giving credit card details. This is shown by the lock icon on the bottom right of your browser and a web address that starts with https. Of course make sure that the web site where you are going to purchase web radio has the exact product you are after. To help make it easier the following link will take you directly to a just such a site. After purchasing web radio online always check your credit card statements. Identify purchase which you know you have made, like your web radio purchase, and always challenge with your bank any piurchases that you cannot identify. Doing these things will ensure your online purchases are safe and rewarding.
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