In short: you can’t! Official crappy FortiClient VPN package for Linux doesn’t support IPSec VPNs. But there’s an alternative package which supports IKEv1.
ShrewSoft VPN client, despite not being developed since 2013, works fine. Maybe because Forticlient still uses aged protocols… 🙂
I followed this XModulo guide which is basically good except for few things which needs to be actualized.
Let’s go straight to the compilation and installation
apt install cmake libssl-dev libedit-dev flex bison qt4-default qt4-qmake wget https://www.shrew.net/download/ike/ike-2.2.1-release.tgz -P /tmp tar -xvzf ike-2.2.1-release.tgz -C /tmp cd /tmp/ike cmake -DCMAKE_INSTALL_PREFIX=/usr -DQTGUI=YES -DETCDIR=/etc -DNATT=YES make sudo make install sudo ldconfig sudo mv /etc/iked.conf.sample /etc/iked.conf
Now the package should be installed. Launch
to start the backend daemon, and for the GUI: