This is what Morpheus said to Neo in the movie "The Matrix".  And it's so very true regarding information security.  

Intruders don't care about what you're thinking about your network security. They just peek and poke until they find a hole that you would not have thought existed.

Check! Your! Facts! Know your network. If you're not sure - just check, don't speculate!

It's the same for general troubleshooting problems and for information security. I am seeing…