如何在wifi源丢失连接时检测到网络可达性的丢失？

I am trying hard to get the authentic internet connectivity status. I have used Apple's Reachability but it's only giving me the status of wifi connectivity i.e. not covering the case when the device is connected via wifi (to a router or hotspot), but the wifi router or hotspot itself is not connected to the internet. This scenario is reproducible by pulling the internet input cable from wifi router. The reachability's notifier returns I am trying hard to get the authentic internet