Question:
I have a Plug and Play Scada server with a fall-back mechanism that switches my server to iBurst when the ADSL is down. So, basically, we have two gateways on
our system. The problem is that sometimes I cannot connect to my server's domain, e.g. myserver.pnpscada.com.
I suspect, after talking to someone at Plug and Play Scada, that every time the ADSL is down for a short while, the system switches over to to iburst router,
with a different external IP, and then it takes a long while before the domain name switches back. Is it possible to hardcode the domain name on the ADSL inetner IP?
The problem is made worse by the fact that there are GPRS modems that connects to the server on this dynamic dns domain as well.
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Ok, I just checked and it is back on the iBurst IP.
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It is now 9 minutes later, and one of the modems has just connected on the new IP, but my web page doesn't work now. A very complex problem

Answer:
1. What is the use of a useless fallback? A fallback should keep the same internet IP, otherwise it is essentially useless, since clients will cache the IP of the domain name, and fail to contact the server reliably. I know that some ISP companies in South Africa offer that service, e.g. Internet Solutions.
2. The Plug and Play Scada server keeps a TCP connection open to the central server. This connection will break when the IPs change, and be reconnected over the new IP. At that time the central server will register the new IP on the server's domain name (Dynamic DNS). It will also set the subdomain of the organization that was set to that box. But that process takes maybe 10 minutes, so you have probably a minimum of 10 minutes when you can't contact the server on the domain name, and client devices and machines will cache the IP for the DNS anyway, which means you may not be able to contact it until you restart your internet explorer, or indefinitely (or until you reboot your client device).
3. There is a way to fix the DNS to a specific IP. We're using that in some corporations where the originating IP and the destination IP are different. It is accessible on the Communication settings screen in Plug and Play Scada web site, I think. You should have access if you own the box.