2017_07_12_dns_localhost_resolution_2

$ cat /etc/hosts
127.0.0.1               localhost
::1         localhost

$ host 127.0.0.1
1.0.0.127.in-addr.arpa domain name pointer localhost.

$ host  localhost.
Host localhost. not found: 3(NXDOMAIN)

$ grep "^hosts:" /etc/nsswitch.conf
hosts:          files nis dns myhostname

# Adding "localhost    127.0.0.1" to /etc/hosts:

$ nl /etc/hosts
     1  127.0.0.1               localhost
     2  ::1         localhost
     3  localhost       127.0.0.1

$ host 127.0.0.1
1.0.0.127.in-addr.arpa domain name pointer localhost.

$ host localhost
Host localhost not found: 3(NXDOMAIN)