posted by qubix on April 10, 2020

If you have installed virtualmin and csf spi firewall and you see the warning

"Check for DNS recursion restrictions in Virtualmin"

after you hit "Check server security button"
here is what you have to do to avoid your dns server being used for random queries by random ips:

1) Go to Webmin -> Servers -> Bind DNS server
2) Hit "Edit config file"
3) place before "options {" the following

acl "trusted"{;};
4) inside options block now place the following

    recursion yes;
    allow-recursion { trusted;};
    allow-notify { trusted;};
    allow-transfer { trusted;};
    forwarders {;};

5) save and restart dns server