Install charon-cmd by entering the following commands in the terminal:
sudo apt update sudo apt install charon-cmd
standalone IPsec client
The strongSwan VPN suite uses the native IPsec stack in the standard Linux kernel. It supports both the IKEv1 and IKEv2 protocols. . This package contains the charon-cmd command, which can be used as a client to connect to a remote IKE daemon.