A connection between the subnets behind the gateways <b>moon</b> and <b>sun</b> is set up.
The authentication is based on <b>X.509 certificates</b> which contain a <b>critical</b> but
unsupported 'strongSwan' extension. Whereas <b>moon</b> ignores unsupported critical
extensions by setting <b>libstrongswan.x509.enforce_critical = no</b> in strongswan.conf,
<b>sun</b> discards such certificates and aborts the connection setup.
