Ubuntu Servers :: Share Internet Connection To Client Using NAT

I am back to the same issue internet connection sharing using NAT .I use the following command it work for me for an hours.

Code:
sudo iptables -A FORWARD -o eth0 -i eth1 -s 192.168.0.0/24 -m conntrack --ctstate NEW -j ACCEPT sudo iptables -A FORWARD -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT sudo iptables -A POSTROUTING -t nat -j MASQUERADE

Code:
sudo iptables-save | sudo tee /etc/iptables.sav
Edit /etc/rc.local and add the following lines before the "exit 0" line:

Code:
iptables-restore < /etc/iptables.sav

Code:
sudo sh -c "echo 1 > /proc/sys/net/ipv4/ip_forward"

After restarting my server NAT is not working .client system can ping to my server through the server's eth1 ip but Internet is not accessible to the client pcs.