To be able to use VPN to access the GFZ network you have to activate VPN on the "Passwords & Services" site on the intranet.
In case this is the first time you establish a VPN connection via ASA, you need to install the Cisco AnyConnect client.
Go to asa.gfz-potsdam.de.
Select "GFZ employees" and click Login.
In the new window, log in with your GFZ username and domain password.
Then enter the code from your 2-factor authentication device.
Click on "Download for macOS".
Open the downloaded .dmg file and double click on the .pgk file.
Follow the instructions and then click on 'Install'. Enter the password of your Mac.
Open the Cisco AnyConnect Client.
Enter "asa.gfz-potsdam.de" as server address and click on "Connect".
Select "GFZ-Mitarbeiter" as the group.
In the new window, log in with your GFZ user name and domain password.
Enter the code from your 2-factor authentication device in the "Token" field.
Click on "Log in". The VPN connection is established.
In your menu bar, you will now find the VPN client icon. Use it to disconnect, reconnect or exit the Cisco AnyConnect Client.