num.to.			30 IN SOA master.dns.ne.jp. tech.sakura.ad.jp. (
				2020101500 ; serial
				3600       ; refresh (1 hour)
				900        ; retry (15 minutes)
				3600000    ; expire (5 weeks 6 days 16 hours)
				3600       ; minimum (1 hour)
				)

num.to.			30 IN A	160.16.209.212

Mail exchangers:
num.to.			30 IN MX 10 mail.num.to.

Name servers:
num.to.			30 IN NS ns1.dns.ne.jp.
num.to.			30 IN NS ns2.dns.ne.jp.