As you may have already noticed, the Internet uses names as well as numbers to allow computers to locate other computers. This can speed up the connection to another computer considerably, since you do not have to rely on a DNS server to translate a name for you. Occasionally, a DNS server may be busy or slow, especially during peak usage times on your network. It is not ready for actual use without a little minor editing.
Entries are case-sensitive.
Therefore, it is a good idea to assign multiple host names with different cases. A loopback address is simply a method of describing your own computer to itself. Names are read in a linear fashion, from top to bottom. You should place the most commonly used names should near the beginning of the file.