Forticlient for Linux can be found in the Downloadbereich
Configuration: Create a directory .fctsslvpn_trustca in your home directory and save the current certificate chain (Zertifikatskette) in this directory. Start ./fortisslvpn.sh for the first time as root and enter vpn.oth-aw.de as the server, in the field behind 443. Username and password as usual. Under Settings you can also save the configuration permanently. Now you can connect via VPN. If you have problems with the Forticlient in your Linux distribution, you can also try openfortivpn.
MAC iOS devices can also find the Forticlient in the APP store.
For Android you can also download an Android client via www.forticlient.com.
Alternatively, it is also possible to connect via openfortivpn via vpn.oth-aw.de. (Host:vpn.oth-aw.de, Port 443)