Binary package “strongswan-ike” in ubuntu xenial

strongSwan Internet Key Exchange daemon (transitional package)

 The strongSwan VPN suite uses the native IPsec stack in the standard
 Linux kernel. It supports both the IKEv1 and IKEv2 protocols.
 .
 This package used to install version 5 of the charon daemon and has been
 replaced by the strongswan-charon package. This package can be safely removed
 once it's installed.