I am just wondering if anyone has seen duplicate ping in Linux? I investigated a little bit and found that i get duplicate ping only from the DMZ range where the Linux box is and to one other specific range on across the VPN. I made sure that all interfaces on routers and firewalls have correct ip addressing and they do not have a broadcast IP. Any ideas are welcome. I also checked routing and everything is routed as it should be? Where could a problem be?