Domain zone file
$TTL 3h
; value that instructs non-authoritatively DNS servers how long to keep the data in cache
@ TTL IN SOA primary_nameserver. email_address. (
1000
; serial number – to be increased with each zone file modification
86400
; refresh – TTL for the secondary or slave server – after this time the slave/secondary will query the master
7200
; retry – in case of failure of the above
360000
; expire – after a failure this long of the master, the secondary/slave will no longer be authoritative
7200
; minimum – TTL for negative answers cached on non-authoritative DNS servers
)
domain_name. TTL class(IN) type(A,CNAME,MX,PTR,etc) value
Delegation
In order to delegate another DNS server with a specific subdomain you need two entries:
subdomain. NS subdomain_nameserver.
subdomain_nameserver A name_server_ip