I originally posted on this on the Bluetooth forum since the connection from my PC to the phone is via BT. But BT seems to be fine since the DUN dials out, the phone apparently connects to the VF network but I can't actually access anything.

This is occurring on both a P1i and K800i

After the dialing is complete there is a connection between the PC and the phone over BT I see the following on my PC's network configuration
PPP adapter BluetoothConnection:

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : BluetoothConnection
   Physical Address. . . . . . . . . :
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   IPv4 Address. . . . . . . . . . . : 121.90.232.58(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.255
   Default Gateway . . . . . . . . . : 0.0.0.0
   DNS Servers . . . . . . . . . . . : 202.73.206.16
                                       202.73.198.16
   NetBIOS over Tcpip. . . . . . . . : Enabled

This looks all quite reasonable except there is no gateway address which might explain why I can access the Internet. The phone itself accesses the Internet fine using builtin mail and browser software over a 3G (or GPRS ) connection.

The log for the connection only shows bytes out - no bytes returned.

It's unlikely but wonder if it's a problem with VF - guessing not else more would have complained by now.

Not sure what else to look for.