When I make test on dnsreport.com it retrive a report contain fail row that about test name
"Open DNS servers"
And contain this information:-
ERROR: One or more of your nameservers reports that it is an open DNS server. This usually means that anyone in the world can query it for domains it is not authoritative for (it is possible that the DNS server advertises that it does recursive lookups when it does not, but that shouldn't happen). This can cause an excessive load on your DNS server. Also, it is strongly discouraged to have a DNS server be both authoritative for your domain and be recursive (even if it is not open), due to the potential for cache poisoning (with no recursion, there is no cache, and it is impossible to poison it). Also, the bad guys could use your DNS server as part of an attack,
Yes, it is important to close DNS servers, or at least turn recursion off. This should do the trick for you.
1. SSH Into your Server
2. Do a nano -w /etc/named.conf
3. Search for // query-source address * port 53;
4. Type Recursion no;
5. Save and Restart Bind
WARNING: Since there are multiple A records for one or more of your NS records,
the DNS report could not determine if the glue provided by the parent servers match
that provided by your authoritative DNS servers.
This does not indicate an error, but you should verify that the IPs are correct.