Bind9 does not work from the internet. how to fix?

Question

linux

In short, the situation is this
Put shorter bind9 set to configure locally everything works and ya.ru redirects to 192.168.1.1. Internet access is shorter.
I put my external ip in dns (I took it from 2ip.ru) everything works.
In short, I tried it with a friend, it doesn't work! It says that the server ip was not found.
but! ping ya.ru shows 192.168.1.1 . Tobish that that I registered in manual works. And the fact that he should receive from a higher standing dns is not!
What could be the reason ?
which file to edit?
etc/bind/named.conf.local

//
// Do any local configuration here
//

// Consider adding the 1918 zones here, if they are not used in your
// organization
//include "/etc/bind/zones.rfc1918";


zone "example.com" {
  type master;
        file "/etc/bind/db.example.com";
};

zone "ya.ru" {
  type master;
        file "/etc/bind/db.ya.ru";
};

zone "vk.com" {
  type master;
        file "/etc/bind/db.vk.com";
};

Answer 1

what does it show?

nslookup ya.ru your_ip_address_dns