Can't access mapped drive while connected by modem

[HD101]

XP Pro SP2 system - Firewall is off.
Drive F is mapped to network shared folder.
While connected to outside company by modem, the user can't access the mapped drive. The system says it is disconnected. But the moment I disconnect the dialup connection, the drive is ok again. Anyway around this problem?
Is the problem that the PC can't connect to two networks at the same time?

 

[bcastner]

Is this a VPN connection?

 

[HD101]

No, just modem dialup. If we could use VPN that would be great but the outside company doesn't use VPN.

 

[HD101]

Would this be a Multihomed problem? Since the PC is connected to both a LAN (by network adapter) and the other company's network (by modem), is there some kind of configuration change I need to make? The OS is XP Pro SP2.

 

[HD101]

Ok, the answer is

http://support.microsoft.com/default.aspx?scid=kb;en-us;262397

Once I added the route to allow the users computer to access the server everything worked fine. Added this command at the command prompt:

"Route add 192.168.2.0 mask 255.255.254.0 192.168.1.0 metric 2 -p"

This allowed the users computer at 192.168.1.12 to go thru 1.0 to 2.0 to access the server at 2.20