I have 6 remote sites each with 5 - 7 PC's and 3 - 4 printers using JetDirect devices. Each site has static IP's and accessing the internet with their own DSL (SBC) at their respective sites. Each site has Nokia IP30's (with Check Point) to access via VPN the main (7th) site. The main site has a Check Point 225U device which is connected to a T1 (running only 768 for data). The T1 is supplied by TDS Metrocom. The remote sites access the main site to login to a Windows 2000 network running active directory and to access an IBM AIX box (using MultiView 2000). All PC's at all sites are running XP Pro with at least SP1 on them.
The remote sites need access to the main site for email (Exchange - lets call it Exchange); files (lets call it FS1) and the AIX box. All sites communicate via TCPIP. The main site is using DHCP. All remote sites have the IP address of the 2 servers in their HOSTS file.
The issue were are having is unreliable communications between the remote sites and the main site. Login to the domain is usually OK but Outlook access to the Exchange box is unreliable. Sometimes it is ok but others it gives Exchange cannot be found Retry, Work Offline or Cancel. If you hit Retry 3 - 4 times, sometimes is connects.
Also, maybe unrelated, is the Telnet software (MultiView2000) just stops repsonding. There could be days where the software loosed connection every hour or so.
The DSL speed at all but 2 sites is around 1.2 to 1.5 MBS while the 2 slow sites are around 384 K (since they are so far away).
I set the MTU's on the PC's at 2 sites to test - does seem to make much difference.
Any ideas on how to improve this situation?