Model Zone File Explanation $ORIGIN model.com. $TTL 1h model.com. IN SOA ns.model.com. username.model.com. model.com. IN MX 10 mail.model.com. @ IN MX 20 mail2.model.com. @ IN MX 50 mail3 model.com. IN A 192.0.2.1 ns IN A 192.0.2.2 www IN CNAME model.com. mail IN A 192.0.2.3 mail2 IN A 192.0.2.4 mail3 IN A 192.0.2.5