192.168.1.1             host1.example.com
192.168.1.2             host2.example.com
192.168.1.4             host4.example.com
2001:db8::2:1           host1.example.com
2001:db8:0:1:1:1:1:1    host2.example.com
2001:db8::1:0:0:1       host3.example.com

#next line is empty for coverage

//empty_line_for_coverage


#next line has invalid address for coverage
1.2.300       doesntexist.com