Network name database
/etc/networks
The networks file contains information regarding the known networks that make up the DARPA Internet. For each network, a single line should be present with the following information:
official_network_name network_number aliases
Items are separated by any number of spaces or tabs, or both. A pound sign (#) in a line indicates the beginning of a comment—any characters after a #, up to the end of the line, aren't interpreted by routines that search the file.
The network number may be specified in the conventional “.” (dot) notation using the inet_network() routine from the internet address manipulation functions, inet_*(). Network names may contain any printable character other than a field delimiter, newline, or comment character.