On a users machine when outlook is opened the mailbox opens in just a few seconds like it should. But when I go to open the calendar, this process can take several minutes to complete. It will sit and hang like it is busy. I ran outlook.exe /rpcdiag and it showed me the calendar request was trying to open "mail.companydomain.com" versus using 2k11sbs.companydomain.com (internal name). Other requests all use the 2k11sbs.companydomain.com which is the internal server name vs the external DNS name. I can't seem to find out where the calendar is trying to open the external DNS name from.