/etc/sysconfig/iptables how to set -t nat -A POSTROUTING ?

mattywix · #1 22nd February 2008, 09:50 AM

Hi
How can I add the following in /etc/sysconfig/iptables ? The format of the file doesnt seem to allow this...
/sbin/iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
echo "1"> /proc/sys/net/ipv4/ip_forward

nucleo · #2 23rd February 2008, 02:11 AM

Hi

Code:

service iptables save

saves the output of iptables-save to /etc/sysconfig/iptables

Quote:

net.ipv4.ip_forward = 1

in the file /etc/sysctl.conf enables forwarding

joseCuervo · #3 20th April 2012, 10:02 AM

My laptop is on the LAN (with address of 192.168.0.2) and it can ping 192.168.0.1 but it cannot ping www.google.com
I want to use p1p1 (a.k.a. eth1) as 192.168.0.1 and route everything from 192.168.0.2 through eth0 to access internet but cannot figure out how to add simple NAT commands to iptables script ...

====================================

on Fedora release 16 (Verne)................ there is no "service iptables save" command (the original post is old from 2008)

Code:

[root@ezcorean sysconfig]# service iptables save
Redirecting to /bin/systemctl  save iptables.service
Unknown operation save
[root@ezcorean sysconfig]#

I have enabled

Code:

# Controls IP packet forwarding
net.ipv4.ip_forward = 1

in /etc/sysctl.conf

however, I still do not know how to add the rule

Code:

-t nat -A POSTROUTING -o eth0 -j MASQUERADE

to /etc/sysconfig/iptables

If I do so, /var/log/messages says:

"Line 13 seems to have a -t table option." and it fails to start iptables.

However, if I run

Code:

/sbin/iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

I can access the internet from my laptop as described above.

I suppose I should just add

Code:

/sbin/iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

to /etc/rc.local ??