However, that requirement only kicks in if we host it for them. They stuck by the 100% number, saying the application should stay active even in the event of a flood. I had a discussion with the client today and they clarified on the issue. It seems that if they lose Internet connectivity then we would have to do a DNS change to forward traffic to the external machines. Quite frankly, I haven't the foggiest idea of how this might be possible. Now we know there is absolutely no way to resolve it for internal people (carrier pigeon?), but they want the external users to not even notice. They want us to maintain an off-site copy of the system that in the event of a serious failure at their premises would immediately pick up and take over. It is accessed by both internal and external people. In a nutshell, the application will live on servers within the client's network. However, from a networking issue I just can't seem to figure out how to make it work. It was designed to be able to scale out across multiple database servers, etc. From our web application's viewpoint, this isn't an issue. They want 100% uptime with off-site failover on a web application. We received an interesting 'requirement' from a client today.

Windows internet uptime application