It does more than intended; apart from denying messages to that
particular interface it also denies all messages non-qualified with an
interface globally. This blocks messages completely unrelated to
strongSwan's VPN plugin, such as NetworkManager communication with the
VPN plugins.
From the dbus-daemon manual:
Be careful with send_interface/receive_interface, because the
interface field in messages is optional. In particular, do NOT
specify <deny send_interface="org.foo.Bar"/>! This will cause
no-interface messages to be blocked for all services, which is
almost certainly not what you intended. Always use rules of the form:
<deny send_interface="org.foo.Bar" send_destination="org.foo.Service"/>
We can just safely remove those rules, since we're sufficiently
protected by the send_destination matches and method calls are
disallowed by default anyway.
Closesstrongswan/strongswan#42.
Lubomir Rintel