I have a PowerDNS based master nameserver with 3 slaves. Zone transfer works through AXFR (automatically once every hour it gets checked by the slaves). When I change a record through our panel the notified_serial gets updated correctly as well as the serial in the SOA record.
The nameserver uses a MySQL backend. The slaves don't get notified when changes occur. Nothing is logged when it was supposed to send a Notify. When I force a notify (like: pdns_control notify example.com) the slaves get notified properly.
The config is as follows:
master=yes setuid=pdns setgid=pdns local-address=xx.xxx.xx.xxx allow-axfr-ips=xx.xxx.xx.xxx use-logfile=yes log-dns-details=yes log-failed-updates=yes logging-facility=0 loglevel=4 launch=gmysql gmysql-host=localhost gmysql-user=xxxxxxxxxxxxxxxx gmysql-password=xxxxxxxxxxxxxxx gmysql-dbname=powerdns