Difference between revisions of "VPN"

Latest revision as of 19:21, 3 April 2014

VPN stands for Virtual private network (see also Wikipedia). It enables you to connect to the internal University network without having to be in a physical location near the University. If you are inside the internal University network, you can access a wide range of University webpages and services that are not accessible from outside, e.g. free scholarly articles in journals which the University holds a subscription to.

Once you enter the Uni network, your computer's IP address will change to one that starts with 134.2., so other computers or web servers can easily see that you're inside the Uni network. Please note that this may cause problems if you're logged into a web account while establishing a VPN connection. So, make sure to sign out of your email account, chat, or other accounts before using VPN.

Important: The ZDV is switching to a new VPN service. The old service will no longer be available after September 30, 2013. For more information, please read

• the official announcement
• the new instructions on setting up a VPN client and connecting to the Uni network

Do I need a VPN connection?

Please note that if you are already inside the university network, you do not need a VPN connection. This is automatically the case if you

• are working on any computer of the university
• are using the wireless internet connection provided by the university
• are using the Internet connection of a dormitory which uses the university network.

How do I know whether I am inside the uni network?

Look at your public IP address. If (and only if) it starts with 134.2., then you are inside the university network. To look up your public IP address, google for 'my IP address'.

Setting up a VPN client

The Fachschaft Informatik provides thorough instructions in German.

First of all you need to get an account from the ZDV, which every new student gets automatically after enrollment. The ZDV username usually starts with zx.... Once you have an account, follow the procedure for your favorite operating system.

Ubuntu 8.10 and higher with the Gnome desktop environment

See also the instructions on Mirko Windhoff's website.

Installation

Make sure that you have the following package installed: network-manager-vpnc. You can either install it from your favorite package manager or open a terminal and type sudo apt-get install network-manager-vpnc. The password you are prompted for is your own Ubuntu login password. Confirm all other prompts.

Configuration

Left-click on the Network Manager icon, go to VPN Connections -> Configure VPN....

It should open the VPN tab of the Network Connections preferences. In this window press the Add button.

Which will prompt for a VPN Connection Type, where you should choose Cisco Compatible VPN (vpnc) and press Create.... If the option Cisco Compatible VPN (vpnc) is not available, don't choose anything else! This means you haven't installed the package network-manager-vpnc.

In the next window you should fill the connection settings as following:

Connection Name: anything you like, e.g. Uni-VPN

Gateway: vpn-i.uni-tuebingen.de

Group Name: belwue

Group Password: WLANdle

User Name: your user name from ZDV

User Password: your password from ZDV (or disable the save option to be prompted for your password every time you connect)

Leave the other fields at their default values, but consider whether you want to uncheck the box available to all users. Press OK to save.

Linux using the command line

You need to install the packages network-manager-vpnc and vpnc. To do so, type sudo apt-get install <package name>.

The settings are made by putting configuration files into an appropriate directory (/etc/vpnc on Ubuntu). This needs superuser rights! Call your configuration file something that's easy to memorize, e.g. uni-vpn.conf. Put this text into it:

Interface name vpn
IKE DH Group dh2
Perfect Forward Secrecy nopfs
IPSec gateway vpn-i.uni-tuebingen.de
IPSec ID belwue
IPSec secret WLANdle
Xauth username <your ZDV username>

Depending on your internet service provider, the configuration of your home network, and the position of Jupiter relative to the constellation of Orion, you might need to add the following line to connect successfully:

NAT Traversal Mode cisco-udp

Do not put your password into the configuration file in clear text!

Connecting to VPN

Ubuntu 8.10 and higher with the Gnome desktop environment

Left-click on the Network Manager icon, go to VPN Connections and click on the name of the VPN connection you set up earlier.

Notice that the icon of the Network Manager changes once you are connected to VPN.

Congratulations! Now you can use the Internet

Linux using the command line

Gain super user rights and type vpnc <name of your configuration file> to connect, or vpnc-disconnect to disconnect.

Windows and Mac

Users of Windows and MacOS(X) please refer to the official instructions from the ZDV.

How to use the wireless internet inside the University?

A VPN connection is not necessary any more to use the wireless internet at the University. Please see our FAQ for details.