If we would like to hide version of our bind server and make it harder for bot to sniff what version you use (assuming you always update 😉 ) you can make it by editing file: /etc/bind/named.conf.options:
#lets add this into 'options {'
version "unknown";
#or use other text in brackets
Restart service:
service bind9 restart
Use dig to check that version you use now:
dig @example.com -c CH -t txt version.bind