.

Go to Network Settings under the network icon at top. Select “+” at
lower left. In box that pops up, choose to Create a VPN. In the next
box (it may be hidden behind the one already open), choose PPTP
connection type.

Choose a name for the connection. In the next box, set Gateway =
vpn3.near.uiuc.edu, then under the VPN tab set NetID and password.
Then choose Advanced.

This is the tricky bit. In the next box

select MPPE, set security = 128-bit. It seems that 40-bit also
works, but don’t choose “All Available”, because that doesn’t seem
to work at all.

To start VPN, select it in the network icon on the top bar (I had to
try this twice.)

You can access these settings by Network Setting->select VPN->Configure.

This is based on the contributed settings for Ubuntu 10.04 and Debian 6; I experimented,
and it seemed that the additional changes described there didn’t make any
difference.