We have a pair of Exchange servers (MBX/HT/CAS) deployed on a different network behind a seperate firewall for security reason, and noticed a lot of traffic over dyanmic ports. Many of them are used by MSExchangeRepl, MSExcchangeMailboxReplication, W3WP. I suspect these are RPC dyanmic ports. What's the best way to limit the dynamic range? The servers are Win2008 R2, Exchange 2010 SP1, there is no other applications other than backup, monitoring agent, AV. Static port assignment is used for Client RPC, IS, AddressBook. I came across a few relevant articles and each use a different methods, I am confused and looking for help: http://support.microsoft.com/kb/154596/en-us http://support.microsoft.com/kb/929851/en-us http://support.microsoft.com/kb/908472 PS: Stupid me, I just run "rpccfg –pe 45000-50000 –d 0" on a pre-production server and it screwed up the RPC calls, Exchange wont even started now. Can someone tell me how to fix it? Lucky there is no user on the server.