question about Subdomain query to Domain

[Truong Tan Son]

Dear Sir,

My server currently is running Bind 9, and have trouble to query to root domain server.

domain name:            domain.com
server-ip                   root.domain.com (xx.xx.xx.10)

subdomain name:     sub.domain.com
sub-server-ip:          dns1.sub.domain.com (yy.yy.yy.20)


I setting on   yy.yy.yy.20 :

#/etc/named.conf
....
zone "sub.domain.com" IN {
        type master;
        file "/var/named/sub.domain.com.db";
        allow-transfer { xx.xx.xx.10;};
};

#/var/named/sub.domain.com.db:
....
                                  IN      NS      dns1.sub.domain.com.
                                  IN      NS      root.domain.com.
root.domain.com.       IN      A         xx.xx.xx.10

mail                            IN      A        yy.yy.yy.ab
www                          IN      A        yy.yy.yy.cd


DNS clients using yy.yy.yy.20 (dns1.sub.domain.com) can not query  records of  xx.xx.xx.10 (root.domain.com).

Do I have missing on config file above ?


Thanks you and best regards,
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