Private match "Lost connection to host"

[WickedSick]

Hey.
I recently started using plutonium on two separate PCs.
The problem is internet connection is not available for long-terms here.
Therefore i should close the internet availability of the router (while both PCs are connected to the router, only 'internet' would be terminated).

I still seem to be connected to the match for a minute, i see other player hasn't timed out and both players totally synced, but after a minute the guest gets a "lost connection to host" error.
Any ideas?

[WickedSick]

Anyone?