BIND: hide information about service

example:
dig version.bind txt chaos @DNS-hostname
«9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6_4.6»

dig hostname.bind txt chaos @DNS-hostname
«home-server»

edit /etc/bind/named.conf.options (somewhere it's /etc/bind/named.conf or /etc/named/named.conf).
and add to section options {
...
version none;
hostname none;

}

/etc/init.d/bind9 restart