i had setup bind dns server on centos. from local lan it will work fine but from remote when i tried to nslookup ..it will give reply like "DNS request timed out...timeout was 2 seconds."

what is the problem?

this is my bind config----

// Red Hat BIND Configuration Tool

options {
        directory "/var/named";
        dump-file "/var/named/data/cache_dump.db";
        statistics-file "/var/named/data/named_stats.txt";
        query-source address * port 53;
};

controls {
           inet 127.0.0.1 allow {localhost; } keys {rndckey; };
};

acl internals {
    127.0.0.0/8;
    192.168.0.0/24;
    10.0.0.0/8;

};

view "internal" {
    match-clients { internals; };
    recursion yes;
    zone "mydomain.com" {
       type master;
       file "mydomain.com.zone";
    };


zone "0.168.192.in-addr.arpa"  {
      type master;
      file "0.168.192.in-addr.arpa.zone";

};

zone "." IN {
        type hint;
        file "named.root";
};

zone "localdomain." IN {
        type master;
        file "localdomain.zone";
        allow-update { none; };
};

zone "localhost." IN {
        type master;
        file "localhost.zone";
        allow-update { none; };
};

zone "0.0.127.in-addr.arpa." IN {
        type master;
        file "named.local";
        allow-update { none; };

};

zone "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa." I
N {
        type master;
        file "named.ip6.local";
        allow-update { none; };
};

zone "255.in-addr.arpa." IN {
        type master;
        file "named.broadcast";
        allow-update { none; };
};

zone "0.in-addr.arpa." IN {
        type master;
        file "named.zero";
        allow-update { none; };
};

};
view "external" {
 match-clients { any; };
    recursion no;
    zone "mydomain.com" {
       type master;
       file "mydomain.com.zone";
   //    file "/var/named/chroot/var/named/mydomain.com.zone";
    };


zone "0.168.192.in-addr.arpa"  {
      type master;
      file "0.168.192.in-addr.arpa.zone";
};

};

include "/etc/rndc.key";