Using netkey and the looopback feature, pluto connects to itself for an SA.
This is used for MLS type labeling of connections on the same host

This tests a problem where a connection between 127.0.0.1 and 127.0.0.01
fails to match the secret:

%any %any 127.0.0.1: PSK "test"

It will match:

: PSK "test"