$ORIGIN example.com.     
$TTL 3600               
example.com.  IN  SOA   ns.example.com. username.example.com. ( 2020091025 7200 3600 1209600 3600 )
example.com.  IN  NS    ns                    
example.com.  IN  NS    ns.somewhere.example. 
example.com.  IN  MX    10 mail.example.com.  
@             IN  MX    20 mail2.example.com. 
@             IN  MX    50 mail3              
example.com.  IN  A     1.2.3.1             
example.com.  IN  A     1.2.3.2
              IN  AAAA  2001:db8:10::1        
ns            IN  A     1.2.3.3
              IN  AAAA  2001:db8:10::2        
www           IN  CNAME example.com.          
wwwtest       IN  CNAME www                   
mail          IN  A     1.2.3.4
mail2         IN  A     1.2.3.5
mail3         IN  A     1.2.3.6
*.www         IN  A     1.2.3.7
a.www         IN  A     1.2.3.8