iOS network reachability - doesn't seem to be working

I'm following How to check for an active Internet connection on iOS or OSX? and http://developer.apple.com/library/ios/#samplecode/Reachability/Introduction/Intro.html to test for connectivity, but am running into some pretty basic issues.

For example, I'm running a .NET API off of another machine and then trying to connect to it via my mac mini.

1) When IIS is running, everything is working like it should, I was excited that I got this working!

2) I can shut off IIS completely (obviously, host is unreachable) but my reachabilityWithHostName is still reporting that the host is reachable.

Any ideas?