I spent the last little hour or two trying to get a VPN working back to my department's network. The IT guys make this a snap for their Windows users, but they haven't gotten around to unsupported operating systems.
This guide is getting OpenVPN working using the Network Manager GUI using Ubuntu 10.4; this guide in particular covers the "Password with certificates" option, because that's what we use.
I wanted to use the GUI that should "Just Work" in Ubuntu. The Ubuntu Documentation is a little old, so I thought a complete write up would help somebody else in a similar situation. Additionally, a number of the problems I came across hadn't been really addressed properly in a clear way in the forums. I've had to relearn this twice now, so I should probably write it down.
Part 1: Basic Setup
Step 1: Acquire Certificates
You'll need the certificates from your OpenVPN server. You'll also need the URL or IP address of your VPN gateway (i.e. server). Your sysadmin can probably help you with this.*
Step 2: Install packages
You'll need to make sure you have all of the right VPN packages, because they don't come by default. Use this command from your favorite terminal:
sudo apt-get install openvpn openssl network-manager-openvpn
Part 2: Use the Wizard
1. Click on the Network Manager Menu on the panel, slide down to 'VPN Connections>' and click 'Configure VPN'
2. In the 'Network Connections' dialog that appears, click 'Add'
3. In the 'Choose VPN Connection Type' dialog that appears, choose 'OpenVPN' and press 'Create'. This opens the 'Editing VPN Connection' dialog in the VPN tab.
4. Under 'Connection Name', give a name of your choosing.
5. You can click the 'Connect Automatically' check box if you like.
6. In the 'Gateway' field, give the domain name or IP address of the VPN server that you got from your network admin. For MSU ECE'ers, this is vpn02.ece.msstate.edu .
7. In type, choose "Password with certificates." If your network uses a different strategy (certs only, etc.) change this here.
8. Give your username and password for your network in the fields provided. You may opt to leave the password blank here -- it will prompt you when you try to connect.
8. For each of the 3 certificate types, give the file name on your system where you placed it. (I have a 'crypto' folder in my home directory where I keep VPN certs as well as GPG and SSH keys). Your private key may or may not have a password associated with it. (I didn't).
9. Click 'Advanced.' If you know that your VPN server uses a custom port, specify it here. Mine used the common 1194. Also, if your VPN uses compression, check the box (mine used LZO). Some VPNs use TCP, but the default is UDP. If yours is TCP, check that box (mine was not). Also, it's likely that your VPN uses a 'Tap' structure; if this is the case, as it was in mine, check that box.
10. Open the IPv4 tab in the 'Editing VPN Connection' dialog.
11. Under method, choose 'Automatic (VPN) addresses only'
12. Click the 'Routes' button, and check 'Use this connection only for resources on its network'. This step makes it possible to use both your machine's local internet and VPN.
10. After those steps are done, restart network manager. I wasn't sure the easy way to do that, so I just rebooted my system.
11. After restart, click the network manager and scroll down to 'VPN Connections.' The new connection you created should be there -- Click it to connect. It should work now!
Hope this helps someone. If you have questions/suggestions, leave them in the comments!
*For fellow MSU ECE'ers, you can get them here if you are on the campus network.