cannot connect to outlook using VPN

[windowsfan]

VPN is between configured between Netvanta router and ISA, it's up and running fine but for some reason I am not able to connect outlook from remote office (with Netvanta router) to exchange server at main office with ISA Server.
Note:ISA server Default Gateway is not IP of ISA. Exhange is not published via ISA.
all outbound protocols are opened from remote office to main office..

 

[mofusjtf]

What are the IP settings of your Outlook clients behind the NetVanta VPN device? IP address, gateway, primary and secondary DNS?

 

[windowsfan]

IP: is 10.10.10.150 (from IP range of the brach office)
DNS is 192.168.100.17/19 (DNS Server at Main office)

 

[windowsfan]

hi mofusjtf ,
Any help please?

 

[mofusjtf]

Sorry, I've been out of pocket for a while. Can you access other resources on your Main office network from the branch? (i.e. file access, intranet, etc.). Are the branch computers members of your domain? Can the uses access OWA?

If you add the main office DNS servers to your branch office workstations this might resolve the issue.