I have configured dns server, and if i enable recursion, I can ping and got the result. [root@seobd ec2-user]# nslookup google.comServer:         52.10.197.195Address:        52.10.197.195#53Non-authoritative answer:Name:   google.comAddress: 216.58.193.78But If I disable recursion, I can't ping my result.configuration:options {        listen-on port 53 { 127.0.0.1; 52.10.197.195; 0.0.0.0/0;};        listen-on-v6 port 53 { ::1; };        directory       /var/named;        dump-file       /var/named/data/cache_dump.db;        statistics-file /var/named/data/named_stats.txt;        memstatistics-file /var/named/data/named_mem_stats.txt;        allow-query     { localhost; 0.0.0.0/0; };        notify yes;        recursion no;        dnssec-enable no;        dnssec-validation yes;};zone iftibd.com IN {        type master;        file seobd.fz;        allow-update {none;};};zone 197.10.52.in-addr.arpa IN {        type master;        file seobd.rz;        allow-update {none;};};[root@seobd ec2-user]# ping google.comping: unknown host google.com
DNS problem > If I disable recursion, I can't ping my result
linux;centos;dns;bind
That is expected behaviour; if you do not allow recursion, BIND wont iterate through the possibilities/servers to eventually got your answer, and thus wont be able to answer. The important part is creating ACLs limiting the networks who can do recursive requests, and avoid an open DNS server that can be and will be abused remotely. I would also advise to add to the top of your options section:allow-recursion { 127.0.0.0/8; x.x.x.x/24; y.y.y.y/24; };where x.x.x.x and y.y.y.y are your netblocks. Have a look at: Whats the difference between recursion and forwarding in bindFor the security implications, please have a look  atOpen Resolver ProjectOpen Resolvers pose a significant threat to the global network  infrastructure by answering recursive queries for hosts outside of its  domain. They are utilized in DNS Amplification attacks and pose a  similar threat as those from Smurf attacks commonly seen in the late  1990s.