About the HOSTS file

About the HOSTS file

HOSTS files were the original mechanism used to resolve an IP address to a name. The HOSTS file is a text file residing on each local machine. Each line of the text file typically contains an IP address of a host and a name for it.

The primary limitation of this name resolution technique is that the HOSTS file is only usable by the machine on which it resides. For example, you could add an entry to Host A’s HOSTS file mapping Host B’s IP address to a name of “Pluto”. Any application running on Host A could then contact Host B using the name “Pluto”. However, Host B would not be addressable with “Pluto” by other hosts since the mapping only resides in Host A’s local HOSTS file. That means another host wanting to contact “Pluto” would need a similar entry in its local HOSTS file. Therefore, HOSTS files are difficult to maintain when you have more than a few hosts, and other technologies such as DNS, DDNS and WINS are often used instead.

One of the advantages of using a HOSTS file is that it is not dependent on a server for name resolution, as is required in the other resolution protocols. For a higher degree of stability it is good to use a HOSTS file on all NiagaraAX hosts.

The HOSTS file is always the first place a host looks for name resolution, and if it finds an entry it uses it and does not check other name sources.