Vista computers have problems establishing VPNs with routers. This can be very frustrating, especially since establishing a PPTP VPN is very simple and easy using XP. One problem that creeps up is the cryptography level that is required in Vista by default. Vista requires 128 bit RC4 ecryption by default. There are 2 remedies for this situation when Vista is giving a hard time about establishing a VPN tunnell.

1. Change the routers VPN settings to 128 bit encryption. This will be harder on computers with weaker processors, and will slow down the communications. It may also require that you reconfigure your older XP computers so that they can communicate over the VPN.

2. Change the crypto setting on the Vista computer by editing the registry.

Click Start, and enter regedit in the search box.

Choose regedit from the search results list, run as administrator, and continue in the UAC control box.

Locate this key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RasMan\Parameters

Create the following subkey, or edit the one there so that it appears as this:

Name: AllowPPTPWeakCrypto

Value Type: DWORD

Value Data: 1

Exit Regedit and restart the computer.