On 05/01/2012 02:03 AM, Barry Brimer wrote: >> Yes, I thought the same but my confusion is that I don't see any rules of >> PREROUTING and POSTROUTING in the /etc/sysconfig/iptables file. >> >> [root at VS01]# cat /etc/sysconfig/iptables >> # Firewall configuration written by system-config-firewall >> # Manual customization of this file is not recommended. >> *filter >> :INPUT ACCEPT [0:0] >> :FORWARD ACCEPT [0:0] >> :OUTPUT ACCEPT [0:0] >> -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT >> -A INPUT -p icmp -j ACCEPT >> -A INPUT -i lo -j ACCEPT >> -A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT >> -A INPUT -m state --state NEW -m udp -p udp --dport 631 -j ACCEPT >> -A INPUT -m state --state NEW -m udp -p udp --dport 5353 -d 224.0.0.251 -j >> ACCEPT >> -A INPUT -m state --state NEW -m tcp -p tcp --dport 631 -j ACCEPT >> -A INPUT -m state --state NEW -m udp -p udp --dport 631 -j ACCEPT >> -A INPUT -j REJECT --reject-with icmp-host-prohibited >> -A FORWARD -j REJECT --reject-with icmp-host-prohibited >> COMMIT >> >> >> But when I check the command iptables -L -t nat I can see the NAT rules >> >> [root at VS01]# iptables -L -t nat >> Chain PREROUTING (policy ACCEPT) >> target prot opt source destination >> >> Chain POSTROUTING (policy ACCEPT) >> target prot opt source destination >> MASQUERADE tcp -- 192.168.122.0/24 !192.168.122.0/24 masq ports: >> 1024-65535 >> MASQUERADE udp -- 192.168.122.0/24 !192.168.122.0/24 masq ports: >> 1024-65535 >> MASQUERADE all -- 192.168.122.0/24 !192.168.122.0/24 >> MASQUERADE tcp -- 192.168.100.0/24 !192.168.100.0/24 masq ports: >> 1024-65535 >> MASQUERADE udp -- 192.168.100.0/24 !192.168.100.0/24 masq ports: >> 1024-65535 >> MASQUERADE all -- 192.168.100.0/24 !192.168.100.0/24 >> >> Chain OUTPUT (policy ACCEPT) >> target prot opt source destination >> >> am I missing something? > Maybe .. do you have IPv4 forwarding enabled? What is the output of > "cat /proc/sys/net/ipv4/ip_forward" ?? If it is 0, then edit > /etc/sysctl.conf .. find net.ipv4.ip_forward .. set it to 1 and then run > (as root) sysctl -p > In the Host machine the ip_forward is 1