Hi all I m having exchange 2003 servers in FE/BE configuration. My FE server is located on DMZ network. Before few day when i restarted my FE server, it takes lots of time to shutdown and startup. When i check the event viewer i found follwing Error in system event. Event Type:ErrorEvent Source:NETLOGONEvent Category:NoneEvent ID:3210Date:2/20/2007Time:10:34:16 AMUser:N/AComputer:EXCHFEDescription:This computer could not authenticate with \\DC.Domain.Local,a Windows domain controller for domain DOMAIN, and therefore this computer might deny logon requests. This inability to authenticatemight be caused by another computer on the same network using the same name or the password for this computer account is not recognized.If this message appears again, contact your system administrator. For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.Data:0000: 22 00 00 c0 ".. After taking long time to startup when i log on to domain it takes 10 to 15 min to login. other then this all other functions of FE working fine, Remote user can successfully connect and use Exchange. I nerver understand whats worng, even i never found any help on microsoft site, Pls Help. Regards swapnil

Hi We found solution. Our network engineer mistakenly block rpc dynamic ports on DMZ firewall. after opening that ports problem resolved.

What are the specific RPC dynamic ports that needs to be opened up?Thanks