This is a quirk with this particular router. In our case (BT Business Hub 3) we had OS X connect to the router with DHCP but the router was set to give OS X the correct external fixed IP Address. I had to play games with the router to have OS Server's external FQDN name on the local network.Don't expect instant installation of Server until this is all sorted. These interactions with external parties can take from many hours to a few days and should be completed to your satisfaction before you unwrap the Server app.So, in the case of our Server's FQDN, we had to tell BT to delegate the DNS to our OS X Server's IP Address. We decided to use OS X Server's DNS to manage all the domains we manage.I had to double and triple check before I realised that I had not told the people selling me our fixed IP Addresses (BT in the UK) the correct FQDN to resolve reverse DNS to.if all its (few) assumptions are met but can cause a right mess if they aren't! You have to get the OS X identity issues sorted before you go ahead with the step of installing the OS X Server app. This will require special attention if you bought a Mac Mini with Server included. Important Note: All this had to be done on OS X before the Server app was installed successfully and running reliably.if your OS X Server is not internet-facing: This was our experience after several failed attempts and several attempts where we thought things were working but Open Directory flaked out. If all this sounds simple - we did not find it so. If there are any inconsistencies between these, then the Server app just can't make all the assumptions about its identity that it needs to. that the DNS records matched exactly the domain name on the SSL Certificate we purchased.I was 100% sure that the OS X Server's DNS and reverse DNS was consistent, as viewed from within and without our network, and.

It was only after the following that Open Directory settled down: But for many months now, though, Open Directory has been working as expected and serves our many users' credentials reliably.

Mac os x server app