I recently installed a wireless setup at a client's location with a Linksys wireless router/switch/NAT/firewall device on an ADSL modem. Wingate VPN client is used on a couple of laptops, and either via wireless or if wired directly to the modem (wireless router completly disconnected), I have a problem with the VPN connection. The same laptops have no problem with the VPN at most Kinkos here in the US, coffee houses, hotels, etc. All PCs, wired or wireless, have no problems with internet access, email, etc. thru the router and modem.
The VPN connection is negotiated just fine, I can open the shared folder area on the VPN server PC (which is on a cable modem w/ Wingate as router/NAT), copy files across the VPN, and open text files. If I try to open a QuickBooks2005 file, or an Excel spreadsheet, however, the connection fails and I get an "error 64: the connection was lost" in QuickBooks, or a "Delayed write error-- the data was lost" error in Excel.
The DSL modem is probably using PPPoE -- is that a potential problem? I did check the MTU on the DSL modem, which was at the default 1500.
Any suggestions are greatly appreciated, as always.
DrJ