Those of you who need to connect to Microsoft VPNs have probably already discovered the wonderful Debian-HOWTO for pptp-linux:
In that case, you've probably noticed the pptpconfig package isn't in the Ubuntu repository. There are a few threads on this forum dedicated to installing it, but if you're VPN needs are relatively simple, I have a python script that might help.
Ubuntu comes with Python pre-installed, so all you have to do is download the script and away you go.
I wrote it entirely for my own circumstances, benefit and education, so I can't give any guarantees it will work for you. But if it doesn't, please let me know so I can fiddle around and see if I can improve it.
It allows you to configure multiple VPNs, and choose which one to connect to. After connection, it automatically determines your IP address and creates what I hope is a suitable route. I believe this is easier than fiddling around with IP tables and such, as the Debian How-TO on sourceforge reccomends.
The script assumes you want to connect a single PC (presumeably yours) to a remote LAN. It definately works from behind a NAT router. It also assumes the VPN will be created using 'ppp0'. If you're already using ppp0, maybe for ADSL, you can probably still use the script if you open it with gedit and 'find and replace' all instances of ppp0 with ppp1.
Obviously, you need to have pptp-linux installed.
You can download my script here. Right click and select 'save link as', otherwise it will just open in the browser window. (It's only a text file, after all)
sudo apt-get install pptp-linux
Save it into your home directory. Before you can run it, you will need to mark it as executable. Open a terminal window and type in
Please read the comments at the beginning of the script before you use it. It contains important information about connecting to Windows 2000 and 2003 servers.
If you are using AMD64 Ubuntu, you will need to edit the script, search for 'mppe', and then comment out the appropriate line. (It's marked with big warnings). Otherwise, your computer will completely lock up on a successful connection. (Though at least you'd know it worked!)
Hopefully, this can make someone elses life easier, too.