Someone

logging {
        channel security_channel {
                file "/var/log/bindsec.log";
                severity debug;
                print-time      yes;
                print-category  yes;
                print-severity  yes;

        };

        channel default {
                syslog          daemon;
                severity        info;
                print-category  yes;
                print-severity  yes;
        };

        category security {
                security_channel;
                default;
        };

        channel specific_debug_level {
                file "/var/log/foo";
                severity debug 3;
        };

        category lame-servers { null; };
        category network { specific_debug_level; };
        category default { default; };
};