Install PPTP plugin for Network Manager
1. Open Add/Remove from the Applications menu
2. Select All available applications from the show dropdown menu
3. Enter pptp in the search box
4. Select VPN Connection Manager
5. Apply Changes to install.
Reboot or Restart the dbus Service
Next, you can either reboot your machine or restart the dbus service and log out and back in. If you’d rather not reboot, follow these instructions:
1. Open a terminal and restart the dbus service with: sudo /etc/init.d/dbus restart
2. Log out of GNOME, or hit control-alt-backspace
3. Log back in
VPN Setup
Entering the details of your VPN is relatively straightforward, with one caveat and a few advanced options.
1. Click on the Network Manager applet in your system tray, and select VPN Connections > Configure VPN…
2. Click Add and follow the wizard to begin configuration. Enter a name for the connection, and the address of the VPN server.
3. IMPORTANT - Switch to the Authentication tab and select Refuse CHAP. This is necessary to connect to a server using the default configuration of the Microsoft PPTP VPN service.
If you have special requirements, or prefer not to tunnel all your traffic through the company VPN while connected, you can specify some advanced options that allow you to customize the connection
* DNS - Deselect Use Peer DNS under the PPP Options tab and Peer DNS through tunnel under the Routing tab if you’d prefer to use your local DNS server for queries.
* Routing - Select Only use VPN connection for these addresses if you know the address or subnet of the machine you’d like to connect to. This is specified using slash (or CIDR) notation. For example, if your workplace network uses addresses on the 10.10.1.0 network, you would specifiy 10.10.1.0/24 to only route those addresses over the VPN.
Connect!
All that’s left now is to connect. Click the Network Manager applet once more, and select the profile you defined in the last step from VPN Connections. Enter your credentials in the authentication screen that pops up, and wait for it to connect. Once connected, Network Manager will display a lock on your connection, signifying that your secure tunnel is in place.
bron:
http://tipotheday.com/2008/04/29/connect-to-windows-vpn-server-pptp-with-ubuntu-hardy-heron/