According to my very knowledgeable server support guy, ISPConfig corrupts the named.conf file by adding an invalid character to it every time a DNS zone is edited
. This of course takes the bind down, making it impossible for the site to resolve properly.
"We also found a problem with ISPConfig, that when you edit a dns zone in ISPConfig, it corrupts the /etc/named.conf file, as it is adding an invalid character that makes bind down. We fixed this by protecting (read only) the said file. After we've done this, all dns problem is corrected, just look into dns report."
So this looks like a bug, we've struggled for three weeks (a nightmare!) to find out why the freaking site was not showing. The developer's may want to make a note and check on this.
Great open source software, although it's convoluted (IMHO) when it comes to DNS settings. Too many settings in non-intuitive places that make configuring DNS a problem. Also, couldn't see manual or tutorial that really covered this. Most of the time I didn't know if the value to be entered was the IP or the nameserver as in "ns1" or whatever. Also, in certain fields it's hard to tell if that should be a domain name or an IP or just a title.