Does it happen when you turn off the firewall?
Now it is not so possible to just turn off the firewall. Firewall is my router+server, so if I just turn it off, I will break many things and I will allow anything usually not allowed. And a machine I playing from is behind this router, I also playing Nexuiz normally (using 26000 udp port number), I see no problem here for other games. I doublechecked iptables logs for any rejected traffic - no results. Did capture - all fine, no rejects or other anomaly.
I recently noticed that "Connection interrupted" and flooding happens in closed areas and when using portals. I can shoot (I hear bullet sounds), but can't move.
Hm, maybe this is just an ISP issue? When I create local server on local network behind router and apply same firewall rules - anything works perfect.
UPD: Discovered that this happens only when ping greater than 150-200.