Hello *,
just to ensure everybody is informed: This seems to be a FreeBSD related problem, as a Debian machine using the same OpenVPN roadwarrior configuration against the same IPFire instance did not suffer packet loss.
Unfortunately, IPsec on FreeBSD using Strongswan does not work very well either, as I could not figure out how to set the routes needed (the actual IPsec tunnel is successfully established, but no traffic will be routed through it). This leaves me with an operating system whose VPN capabilities are not working or poorly documented... :-/
Anyway, IPFire does not do anything wrong here. Just thougt you might want to know. :-)
Thanks, and best regards, Peter Müller