bad udp cksum

I got problem with a host network (pve-manager/3.4-6/102d4547 (running kernel: 2.6.32-48-pve)). I can ping everything from host but can't ssh to it and can't open any www even do apt-get update. I use pfsense inside kvm on the same host as a gateway (which works great) and another openvz guests...