Following this thread, it looks like I am the only one who has concerns about code in the system that will distinguish between production, DR (and maybe even DR test). Most certainly you want such checks only in your own code (which has no errors and does not need testing) and not in the code that application folks write ;-) Otherwise ugly things might happen when you need to move the system to a new machine or so.
When I was involved with this, I tried very hard to make people use functional checks only. So if your application needs to connect to TCPIP, check for TCPIP being present and not whether you're in a situation where TCPIP should not be present.... (assuming something else will arrange to run the alternate stack that prevents the real network to come up in D/R testing). But I think I lost that eventually, and we settled on something in the LOGMSG iirc. Rob
