Lots of applications for this simple command.  Yesterday, I was troubleshooting a SQL connection issue and even though I had enabled TCP/IP in protocols, I was still unable to make a connection.  As a sanity check, I ran a shortened version of the command below which showed me that 1433 was not open and ultimately brought me to the source of the problem. 

Launch a Command Prompt as the administrator (right click, CMD, select Run As Administrator).

Enter the following command:

Life was simple with Exchange 2003 but as life goes on, newer versions of Exchange have appeared and what was once simple has become a bit more complicated.

One of the first gotchas you notice with Exchange 2007, 2010 and 2013 is the increased security and the challenges of connecting to Exchange remotely.  One tool that I find to be invaluable is the Microsoft Remote Connectivity Analyzer which can identify various issues with your configuration.

I bought a Dell tablet and I really liked it except for when I really needed to get some work done which is when I started hunting for a bluetooth keyboard.  Since I'd already purchased the nifty aluminum keyboard from Apple for my iPad, I connected it to my tablet.  All was well in the world until I started looking for my favorite Windows keys.  Stumbling upon this site, I found that 'some' of the combos work, others not so much but I still think it's helpful nonetheless. 

http://support.apple.com/kb/HT5636

The one that really drove me nuts was the Windows delete key which can be had by simultaneously holding the CTRL and D key.