The strongSwan VPN suite is based on the IPsec stack in standard Linux 2.6 kernels. It supports both the IKEv1 and IKEv2 protocols. . StrongSwan is one of the two remaining forks of the original FreeS/WAN project and focuses on IKEv2 support, X.509 authentication and complete PKI support. For a focus on Opportunistic Encryption (OE) and interoperability with non-standard IPsec features, see Openswan. . This metapackage installs the packages required to maintain IKEv1 and IKEv2 connections via ipsec.conf or ipsec.secrets.