Hello Its really nice to see a detail information about NAT in Linux 2.4 NAT HOWTO.It works well but i have a small problem, i m not able to connect to voice from my internal LAN to the internet. I am giving you the details, which will help you to understand my problem. A----------B----------C | | | D Here A is my windows client with IP address 192.168.101.1 Mask 255.255.0.0 Here B is my Linux7.3 Server with IP address 192.168.0.1 Mask 255.255.0.0 B is also connected to Internet with Generic Serial Modem (ppp0). Here C is my windows client with IP address 192.168.101.3 Mask 255.255.0.0 Here D is my Linux client with IP address 192.168.80.1 Mask 255.255.0.0. I am sharing internet to all my client i.e A, C and D. using this command. > iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE # Turn on the IP forwarding echo 1 > /proc/sys/net/ipv4/ip_forward Upto this everything works fine all clients (A, C, D) share internets. Now if i wanted to start any chat services i.e Yahoo Messenger or vat tool the person who has logged on from A not able to use audio chat to person logged on from C or D. or even a person who is also online from out of this network also not able to call or do voice chat. # I had use this command after that > iptables -t nat -A PREROUTING -i ppp0 -j DNAT --to-destination 192.168.101.3 This time i am able to call people from outside from machine C (192.168.101.3) and also able to do voice conversation in vat. But another side A and D are not able to talk to that person outside the network. Also the above command will not for other hosts A and D. At a time only one machine is able to make a vat connection from B. 1) What should i do so A, C, and D all together can use to call outside and able to do voice conversation in vat? 2) what should i do so A can talk to B in yahoo or vat voice chat? please let me know that is there any solution for my problem? Thanks Regards. Manish. __________________________________________________ Do you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now. http://mailplus.yahoo.com