Message-ID: Content-Transfer-Encoding: binary Content-Type: text/plain; charset="utf-8" References: X-RT-Original-Encoding: utf-8 X-Mailer: MIME-tools 5.508 (Entity 5.508) MIME-Version: 1.0 X-RT-Interface: Web In-Reply-To: Content-Disposition: inline RT-Send-CC: Content-Length: 407 Looking at do_addzone in bin/named/server.c, I see that there's a gap between the check in the view->zonetable to confirm that the zone doesn't already exist and when taskexclusive is started to actually add the zone, so it looks like all it will take is rndc commands recieved sufficiently close together to cause this. Clearly the check for the existence of the zone needs to be in the exclusive section.