I'm familiarizing myself with ISPConfig3 and planning on migrating my existing PowerDNS master/slave setup. Looking at the code and the explanations on how things are supposed to work, I stumbled upon a few strange things. ISC3 uses its own replication/setting synchronization system between its nodes. Slave NS nodes are updated by ISC3, not by standard notify/AXFR mechanisms. According to the PDNS docs, in these cases the native replication should be used which is indicated by setting the zone type to 'NATIVE'. However, in ISPC3 the master and slave zones are trated as such, and master zones are set to 'MASTER' and ISPC3-replicated slaves to 'SLAVE'. This creates unnecessary notification messages and superfluous AXFR replication in addition to the ISPC3-controlled native replication. I haven't configured ISPC for this kind of setup yet, but if I understand everything correctly, this should be fixed.