(Assuming that we are not good at using our brains in the process of cracking network failures, we are simply bound by some conventions and dogmas, which will eventually lead to inefficient cracking of network failures. On the contrary, if we can think out of the box and start from blind spots that we rarely consider to solve network failures, maybe we can get twice the result with half the effort! If you don't believe me, please take a look at the network troubleshooting experience provided below this article.)