to forward log info from syslog to another file for bind9 server in Ubuntu you have to:

1. add logging section in any name.conf* file:

   logging {
       channel bind_log {
       file "/var/log/named.log";
       print-time yes;
       print-category yes;
       print-severity yes;
       };
       category default { bind_log;};
       category xfer-in { bind_log;};
       category xfer-out { bind_log;};
       category update { bind_log;};
       category security { bind_log;};
       category queries { bind_log;};
   };
   

2. update apparmor config by adding to file /etc/apparmor.d/usr.sbin.named

    /var/log/named.log rw, 

3. apparmor_parser -r /etc/apparmor.d/usr.sbin.named
4. service bind9 restart