One of the most useful online tools to come out of Microsoft for the Exchange product is their testexchangeconnectivity site - or to give it's correct name - the Microsoft Exchange Remote Connectivity Analyzer (ExRCA). However the URL is a mouthful, and if you are typing it as often as I do, it is easy to make mistakes.
Therefore I have setup a short URL for it using our Exchange community site exbpa.com - you can get to it via http://et.exbpa.com/
I was going to use te.exbpa.com (which also works) but I thought et would be easier to remember.
Exchange 2003, Exchange 2007, Exchange 2010, MS Exchange Server
Exchange 2003, Exchange 2007, Exchange 2010, MS Exchange Server