Oh that pesky DNS!

I chose "Oh that pesky DNS!" as the title for this post because if you don't get both your internal (private within the corporate network) and external (public facing) DNS right you run into trouble. These days every organization operates in a hybrid mode, the days of only having a network perimeter have gone the way of the moat. So when testing do it both from inside of your corporate network and also from the public side. Wait, the app works when you log in from home but not when you try and log on in the office? First place to look is DNS. Does your internal DNS look like the external DNS that you have setup with your SoA (which stands for Start of Authority; this is an important term and defining what it is should be a part of the hiring process for any IT related jobs). CNAME (canonical name), SRV (service) and MX (mail exchanger), these are all terms that are part of DNS. And don't forget that syntax for all DNS entries has to be perfect, no exceptions. What, I forgot a period at the end of the entry and that is why things aren't working!?!?