Dear list, I'm currently working on setting an OpenBSD server (running on v "4.3 GENERIC#698 i386") to accept incoming ESP traffic (ipv4) encapsulating UDP packets. More precisely, the OpenBSD machine as a server process listening on a UDP port but the I've made sure that only enc0 originating packets can reach the server socket (see PF rules, after this paragraphs of summary). The server has a public IP address, the IPSec authentication is based on public key infrastructure (x509 certificates)....