Overview of DNS Name Resolution
When users type URLs of websites while surfing Internet, DNS name resolution takes place. When two computers (in a LAN or on internet) communicate with each other they use IP addresses to locate and exchange information. It is next to impossible for users to memorize IP addresses of all the servers of the websites that they frequently visit. To overcome this problem DNS servers are configured which receive DNS queries from the client computers and which are the user-friendly names of the sites typed by the users in their web browsers. DNS servers then resolve them to their appropriate IP addresses. For example, if a user types www.yahoo.com in the address bar of the web browser in the client computer and hits enter key, the query is sent to the DNS server which replies back with the IP address of yahoo. Client computer then directly communicates with yahoo server using the IP address resolved by the DNS server.
In order to send name resolution queries to the DNS servers, IP addresses of the DNS servers must be specified in client computers. In Microsoft Windows 7 operating system administrators can assign multiple DNS servers’ IP addresses. It is advisable that the IP addresses of DNS servers of the ISPs, a.k.a. external DNS servers, must be specified in Alternate DNS server field and Preferred DNS server field must be populated with the IP addresses of locally configured DNS servers, a.k.a. internal DNS servers. Internal DNS servers resolve DNS queries for local area network. Computers used in home environments can configure external DNS servers as preferred DNS servers because a home network setup is very unlikely to have a dedicated DNS server installed and configured for name resolution.
Assigning the DNS Server IP Address
Since the process requires elevated privileges, administrator account must be used to specify external DNS server IP address on a client computer. Administrators must follow the steps below to do so:
- Log on to Windows 7 computer with the account that has elevated privileges.
- Click Start and at the bottom of the menu in search box type NCPA.CPL command and hit enter key.
- On the opened window, right-click on the NIC on which the IP address for external DNS server has to be configured, and from the context menu click Properties.
- On the opened box, click Internet Protocol Version 4 (TCP/IPv4) from the available list and click Properties.
- On Internet Protocol Version 4 (TCP/IPv4) Properties box, make sure that General tab is selected and click to select Use the following DNS server addresses radio button.
- Populate Preferred DNS server and Alternate DNS server fields with the IP addresses of internal and external DNS servers respectively.
- Click OK button to close Internet Protocol Version 4 (TCP/IPv4) Properties box, and back on previous box click OK button again to save the changes.