In the server settings where it says IP address, do you enter the local IP address of the server or the WAN address? If I enter the local address, everytime I add a domain it points it to the local address which isnt going to work from outside the network. If I enter the WAN address then all the domains point to 1 site when I view them in the browser.
that explains that, however when I create a new site with the host www it created DNS settings to point the host to the local IP address. Thats no good if I'm using the machine as the name server because it'll send out the local IP for requests to view the domain www.mydomain.com. The way I'm going round it at the minute is creating the site with the host www2.mydomain.co.uk, then creating DNS for www and entering the WAN ip address in.
You can not create the DNS records automatically if you are in a NAT enviroment. ISPConfig is originally build for dedicated servers in datacenters. The solution is: Do not check the Create DNS checkboxes and create the DNS record for your website in the ISPConfig DNS-Manager manually.