Clear OS Community and packet time out in client machines only

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http://serverfault.com – I am having Clear OS Community Edition running as router with 2 network interfaces. Interface eth0 is connected to LAN with ip and interface eth0 with ip is having internet connection. On the Client machine in LAN i have added proper gateway using route add default gw eth0 and i am able to ping gatway. but when making ping request to google.com,i am facing packet loss.But able to see reply in gateway machine through tcpdump.Where can be the problem.Why is the reply packet not reaching client machine and reaching only gateway.There is no firewall in (HowTos)