Was this an actual sendmail server sitting in Clinton's house or was it an offsite server?
http://www.foxnews.com/politics/2015/03/09/location-clinton-...
http://arstechnica.com/information-technology/2015/03/clinto...
Clinton's PR machine claims that the server was in their home:
http://andstillipersist.com/2015/08/new-information-on-the-l...
https://www.washingtonpost.com/investigations/how-clintons-e...
edit: Oh wow, it does. http://support.blackberry.com/kb/articleDetail?articleNumber...
So it may well have been Exchange. How awful...
On a side now, I despise that Gmail dropped ActiveSync support. Hooking up Outlook is a huge pain in the ass, and it's 100% intentional.