allow-transfer defines a list of IP addresses that are allowed to transfer the zone information from server. The default behavior is to allow zone transfers to any host. Even if server wide setting is set to
acl common-allow-transfer {
none;
};
It will be overwritten by zone file.
So, adding common-allow-transfer option will prevent transferring zone file from slave server with such setting set to none.
allow-transfer defines a list of IP addresses that are allowed to transfer the zone information from server. The default behavior is to allow zone transfers to any host. Even if server wide setting is set to acl common-allow-transfer { none; }; It will be overwritten by zone file. So, adding common-allow-transfer option will prevent transferring zone file from slave server with such setting set to none.