Here is the setup:
Win XP x64 on a desktop connected via CAT5e to a Dell TrueMobile 2300. The router is serviced by an SBC ADSL WAN Link. The "server" (x64 desktop) is statically assigned 192.168.1.10 and is set as DMZ on the TrueMobile. The unit is configured to accept outside connections with PPTP and assign them an address from the scope 22.214.171.124 to 126.96.36.199.
When connecting from an off site location we get the "Verifying Username and Password" dialouge and then error out.
1) We have tested it internally. The clients get an IP address within that range and works fine.
2) PPTP/VPN Passthrough is enabled on all involved devices (The TrueMobile has 1723 forwarded).
Any and all ideas are welcome.