This field contains the mappings of IP addresses to host names. Each
entry should be kept on an individual line. The IP address should
be placed in the first column followed by the corresponding host name.
The IP address and the host name should be separated by at least one
space.

valid examples:

192.168.107.246 example.com user.example.com userauth.example.com tools.example.com

192.168.107.246 example.com
192.168.107.246 user.example.com
192.168.107.246 userauth.example.com