Install network-manager-openconnect with the following command in the terminal:

sudo apt-get install network-manager-openconnect
Download the latest Cisco Secure Client (AnyConnect) software for Linux from the ZIH-webpage:
TAKE CARE: check whether the correct link text is displayed in the URL line of the browser:
"https://tu-dresden.de/zih/dienste/service-katalog/arbeitsumgebung/zugang_datennetz/vpn/ssl_vpn"
You should also check the authenticity of the certificate by clicking on the small lock symbol to the left of the URL. The connection must be secure and the certificate valid. Otherwise the website is fake and someone wants to phish your credentials or offer you malware for download, in which case you should contact theService Desk:
In the terminal, navigate to the folder where the file is located, use the cd command.

Navigate to the correct directory
Unpack the file using the following command:

tar xvf filename

Unpacking the file
Navigate to the unzipped folder with cd filename.

Navigate to the unzipped folder
Navigate with cd vpn into the VPN folder.

Navigation into the VPN folder
Execute the following command and enter the password if necessary.

sudo ./vpn_install.sh

Installing Cisco Anyconnect
You will be asked to accept the terms of use, just enter y and confirm. You should receive a success message afterwards.

Accepting the terms of use
Open Cisco Secure Client (AnyConnect) from your programs.

Starting Cisco Secure Client (AnyConnect)
For Connect to, enter: vpn2.zih.tu-dresden.de and confirm by clicking Connect.

Enter server address
Enter your ZIH login in the form zihlogin@tu-dresden.de and enter your password.

Enter access data
You will receive a message that the connection has been successfully established.

Successful connection establishment
To disconnect, you have to click Disconnect in Cisco Secure Client (AnyConnect) .

Disconnect from VPN