[strongSwan] unable to set IPSEC_POLICY on socket: Operation not supported

[Martin Willi]

Rolf,

> Starting strongSwan 5.1.3 IPsec [starter]...
> !! Your strongswan.conf contains manual plugin load options for charon.
> !! This is recommended for experts only, see
> !! http://wiki.strongswan.org/projects/strongswan/wiki/PluginLoad

You should really take this warning seriously, it is there for good
reason. 

> feature CUSTOM:libcharon in critical plugin 'charon' has unmet dependency: NONCE_GEN
> feature CUSTOM:libcharon-receiver in critical plugin 'charon' has unmet dependency: CUSTOM:socket

Your strongswan.conf load statement misses the "nonce" and the
"socket-default" plugins. Just uncomment/remove your custom load
statement, the default generated by ./configure is just fine.

Regards
Martin