How To Masquerade On Linux (Internet Connection Sharing)

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It’s very simple to masquerade (internet connection sharing in Windows language ) on Linux with a few lines of iptables and ip_forward commands.
First of all you have to flush and delete existing firewall rules.
So flush rules by typing in terminal:
iptables -F
iptables -t nat -F
iptables -t mangle -F
Now delete these chains:
iptables -X
iptables -t nat -X
iptables -t mangle -X
Now it’s time to save the iptables rules so type:
service iptables save
service iptables restart
Now all rules and chains have been cleared!
Check it in /etc/sysconfig/iptables which has all default rules set to accept.
Now open /etc/rc.d/rc.local and insert the line:
echo “1″ > /proc/sys/net/ipv4/ip_forwardAnd then save and close the file.
Now asuming that your internet interface is eth0, type:
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
service iptables save
service iptables restart
Note: check if iptables is set to start during boot up.
Or check the status of your iptables service:
chkconfig –list iptables
If level 5 is on then it’s ok othewise start the service at level 5 or level 2345.

It’s very simple to masquerade (internet connection sharing in Windows language ) on Linux with a few lines of iptables and ip_forward commands.
First of all you have to flush and delete existing firewall rules.
So flush rules by typing in terminal:
iptables -Fiptables -t nat -Fiptables -t mangle -F
Now delete these chains:
iptables -Xiptables -t nat -Xiptables -t mangle -X
Now it’s time to save the iptables rules so type:
service iptables saveservice iptables restart
Now all rules and chains have been cleared!
Check it in /etc/sysconfig/iptables which has all default rules set to accept.
Now open /etc/rc.d/rc.local and insert the line:
echo “1″ > /proc/sys/net/ipv4/ip_forwardAnd then save and close the file.
Now asuming that your internet interface is eth0, type:
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADEservice iptables saveservice iptables restart
Note: check if iptables is set to start during boot up.
Or check the status of your iptables service:
chkconfig –list iptables
If level 5 is on then it’s ok othewise start the service at level 5 or level 2345.