51host.net.		30 IN SOA 51host.net. root.51host.net. (
				2018061214 ; serial
				21600      ; refresh (6 hours)
				7200       ; retry (2 hours)
				604800     ; expire (1 week)
				3600       ; minimum (1 hour)
				)
51host.net.		30 IN CNAME df1.51.net.
51host.net.		30 IN CNAME df1.51.net.

df1.51.net.		30 IN A	117.78.34.2
51host.net.		30 IN CNAME df1.51.net.

Mail exchangers:
51host.net.		30 IN MX 10 mail.51host.net.

Name servers:
51host.net.		30 IN NS dns2.51.net.
51host.net.		30 IN NS dns1.51.net.