OpenConnect for Linux
Initial Setup - Step 1
Make sure that your computer is connected to the Internet (or the WLAN with the identification "Uni-Bremen") so that the required software can be installed if necessary. Also make sure that the "universe" repository is activated (see instructions at ubuntuusers.de, for example).
Install the package "network-manager-openconnect-gnome" in the Ubuntu Software Center (or via another package installer) Restart your computer afterwards. If you don't see an option "VPN connection compatible to Cisco AnyConnect (openconnect)" in the selection at step 4 you have to install the package "network-manager-openconnect" also.
Initial Setup - Step 2
Click with the left mouse button on the NetworkManager applet in the panel and select "Configure VPN connections..." under VPN connections.
Initial Setup - Step 3
In the dialog that opens, click on "Add".
Initial Setup - Step 4
Select "VPN connection compatible to Cisco AnyConnect (openconnect)" as connection type and click on "Create...".
Initial Setup - Step 5
You can freely choose the connection name. Enter "vpn.uni-bremen.de" as gateway. Select the file "/etc/ssl/certs/Deutsche_Telekom_Root_CA_2.pem" as the CA certificate.
Initial Setup - Step 6
Under "IPv4 Settings" in the Method tab, activate the setting "VPN, Addresses only" so that only web addresses are routed through the VPN tunnel.
If not all Internet traffic is to be routed through the tunnel (i.e. the tunnel "Tunnel-Uni-Bremen" is to be used, see tunnel types), tick "Use this connection only for resources of this network" under "IPv4 settings" after clicking on "Routes...".
Please note that for access to most media of the "Staats- und Universitätsbibliothek Bremen" all traffic must be routed via the university network. The check mark should therefore be deactivated for this purpose.
Then close all the settings windows you have opened, regardless of whether you have just made the tunnel type setting or not.
Connect - Step 1
Click on the NetworkManager applet again and under "VPN Connections" select the connection you have just set up.
Connect - Step 2
In the opened dialog, check the box "Automatically start connecting next time" and click on the Connect button in the upper right corner.
Connect - Step 3
Enter the access data of your university account under Username and Password and click on Login.
A small lock in the corner of the NetworkManager applet indicates the successful connection.