I have two physical sites. Site A and Site B. Both sites have different Private IP schemes. Site A has Domain Controller + Exchange Server 2003 and also has an ISA 2006 server. Site B also has an ISA 2006 server. The ISA server's in both sites make a PPTP site to site VPN. However, Site A actually has a SonicWALL device which is default gateway for all LAN. So for VPN, a reverse route has been added onto SonicWALL.
For some strange reason, everyday, any domain user that starts her work in Site B, has to PING the server before her Outlook can get connected to the Exchange Server. Similar is the case for any other server. First PING, then any other transport will follow, like Remote Desktop etc.
Just cannot understand what is wrong here. DNS, suffixes etc. is all fine and working.
Please help me understand this scenario.