The DNS Servers are part of the chain which is formed when we make a request, through our browser, of any website.
A DNS server is a computer responsible for resolving existing domain names on the Internet, generating numerical addresses-known as IP (Internet Protocol) addresses - that allow other computers connected to the network, the identification and localization of web sites. In other words, the DNS Server exists to make life easier for the visitor of a website. It provides a comprehensive web address, easy to remember and it speeds up the search of websites on the internet.
This type of computers, which provide services to other computers are called servers, while the ones requesting some services are called clients. Servers that are responsible for transforming domains in numerical addresses use huge databases (Domain Name System) containing information about registered domains on the Internet and their numeric equivalents.
When a user or any company or organization registers a domain if the registration is successful (IE, if the domain is still available and can be recorded), this domain name will be assigned an IP address.
When we want to access the web site via its domain, this request comes to our internet provider or ISP, which sends it to its DNS Server, if the information requested is not found in its database it itself will undertake the same request to another DNS Server and so on until finding it, then returning their corresponding annotation numbers called the IP address, by which computers communicate, to the supplier as well as the exact location of that page, which in turn will send it to us.
The reverse process is also possible, if we know a particular IP and write it in the address bar, it will come back with the domain that corresponds to that IP. This process is faster when the requested page has already been visited by us earlier, because its IP address is already registered in our cache or internet provider cache, so the DNS Servers intervention has not been necessary.
To know the DNS Server that you are using:
Yes, you can change DNS Servers. All DNS Servers are not as fast or efficient so we may be interested in changing them for others. It can also occur on many occasions, that we suffer exasperating slowness when resolving the address of a page. Others we detect problems to access specific addresses (such as international sites). In both situations, it is possible that our operator has some kind of problem with the routing of external addresses. It is also possible that the technical impact falls within the DNS Servers we are using on our Windows network settings to resolve web addresses.
To change a DNS Server we will do the following: in windows XP or Windows Vista we will get to "Network Connections", then we will select "Local Area Network" or "Wireless Network", then "Properties" and with the right button of the mouse we will select Internet Protocol version 4 (TCP / IPv4) and then properties on the lower button, on the general tab uncheck "obtain DNS Server address automatically" and check the box "use the following DNS Server addresses". The lower boxes will be enabled so you can enter the desired primary DNS and the secondary one.
To change them in Windows 7, you will need to go to Start / Control Panel / Internet Network / Network Center and Sharing resources. Then we click on the left column on the Change adapter settings option.
We will now see a window, where, after you click the right mouse button on the WiFi adapter or cable we use to connect to the Internet, we will choose Properties. Then we will go to Internet Protocol Version 4 (TCP / IP), and we will click Properties. A new window will appear, and at the bottom of the window, the DNS servers will be manually inserted.
On the next page you will find a table with the most common internet operators with their corresponding DNS and those of other companies that offer these services as Google.