Basic concepts |
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Basic concepts |
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HostName Commander is a software utility that lets you manage the relationships between the host names and the IP addresses of the computers.
Host name is a textual label assigned to a computer, to distinguish it from other computers on the network. On the Internet, host name has the same meaning as web site name, or domain name. For instance, www.microsoft.com is the host name of the Microsoft's web server. You enter the host name into the address bar of your web browser to tell the browser which server you want to connect to. However, before the web browser can connect to the web server, it must determine the correct IP address of the target computer.
IP address is a set of four numbers, each between 0 and 255, separated with dots. For example, 168.192.0.1 is an IP address. Each computer connected to a network has its own IP address, and the Internet uses the network addresses to direct the data between the computers attached to the network.
Each valid host name is assigned to the appropriate IP address, and the table of such assignments is maintained by the special computers called DNS servers. When you enter a host name into a web browser, the browser sends the host name to the DNS server first, which replies with the IP address that corresponds to that host name. Then the web browser connects to the web server using its IP address. (You might not notice that, because the communication with the DNS server occurs very quickly.)
HostName Commander acts as a negotiator between the web browser and the DNS server. That is, when a web browser or other Internet-related program issues a request to resolve a host name to its IP address, HostName Commander checks the host names that you have set up with it, and if the matching host name found, returns the IP address you have assigned to that host name, without contacting the DNS server. The web browser uses the IP address provided by HostName Commander to connect to the server, again without contacting the DNS server. If you have not set up an IP address for that host name with HostName Commander, the request for teh IP address is passed on to the DNS server, as usual. So, with HostName Commander you can control which servers correspond to the host names, overriding the information provided by the DNS servers.
You can use it to control which servers your web browser connects to when you (or another user of your computer) enter particular host names into its address bar. If you are a web developer, you will find it convenient to use HostName Commander to quickly switch between the development and production servers while working on your web scripts and web pages. Even if you have nothing to do with web development, you can use HostName Commander to block access to specific web sites, by assigning an invalid IP address to their host names. In particular, you can use this ability to suppress the third-party advertisements displayed by many web sites.
