strongswan-charon - 5.9.1-1+deb11u4 main

The strongSwan VPN suite uses the native IPsec stack in the standard
Linux kernel. It supports both the IKEv1 and IKEv2 protocols.
.
charon is an IPsec IKEv2 daemon which can act as an initiator or a responder.
It is written from scratch using a fully multi-threaded design and a modular
architecture. Various plugins can provide additional functionality.