BIND : Configure for External Network2019/10/03

.....
.....
options {
        # change ( listen all )
        listen-on port 53 { any; };
        # change if need ( if not listen IPv6, set [none] )
        listen-on-v6 { any; };
        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";
        secroots-file   "/var/named/data/named.secroots";
        recursing-file  "/var/named/data/named.recursing";
        # change : receive queries from all hosts
        allow-query     { any; };
        # network range you allow to transfer zone files to clients
        # add secondary DNS servers if it exist
        allow-transfer  { localhost; };

        .....
        .....

        # change : not allow recursive queries
        # answer to zones only this server has their entries
        recursion no;

        dnssec-enable yes;
        dnssec-validation yes;

        managed-keys-directory "/var/named/dynamic";

        pid-file "/run/named/named.pid";
        session-keyfile "/run/named/session.key";

        /* https://fedoraproject.org/wiki/Changes/CryptoPolicy */
        include "/etc/crypto-policies/back-ends/bind.config";
};

logging {
        channel default_debug {
                file "data/named.run";
                severity dynamic;
        };
};

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

include "/etc/named.rfc1912.zones";
include "/etc/named.root.key";

# add zones for your network and domain name
zone "srv.world" IN {
        type master;
        file "srv.world.wan";
        allow-update { none; };
};
zone "80.0.16.172.in-addr.arpa" IN {
        type master;
        file "80.0.16.172.db";
        allow-update { none; };
};

# For how to write the section [*.*.*.*.in-addr.arpa], write your network address reversely like follows
# case of 172.16.0.80/29
# network address    ⇒ 172.16.0.80
# network range      ⇒ 172.16.0.80 - 172.16.0.87
# how to write       ⇒ 80.0.16.172.in-addr.arpa