IPTABLES Question

RecoilUK · 09-23-2001, 07:15 PM

Hi guys

I,m trying to work out how to use IPTABLES to set up masquarading but i,m not quite sure what to do, I hope someone can help

I,ve been reading the NAT how-to which says the following...........

4.1 I just want masquerading! Help!

This is what most people want. If you have a dynamically allocated IP PPP dialup (if you don't know, this is you), you simply want to tell your box that all packets coming from your internal
network should be made to look like they are coming from the PPP dialup box.

# Load the NAT module (this pulls in all the others).
modprobe iptable_nat

# In the NAT table (-t nat), Append a rule (-A) after routing
# (POSTROUTING) for all packets going out ppp0 (-o ppp0) which says to
# MASQUERADE the connection (-j MASQUERADE).
iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE

# Turn on IP forwarding
echo 1 > /proc/sys/net/ipv4/ip_forward

Note that you are not doing any packet filtering here: for that, see the Packet Filtering HOWTO: `Mixing NAT and Packet Filtering'.

My question is where do I put the following to first test that it works and then to set it up at boot time, I also intend to set up a firewall of some kind, would I ammend the script i,m about to make with the above for this?

All I have done up to now is to install the IPTABLES rpm from the Mandrake disk.

Thx guys

RecoilUK

mindsurfer · 09-24-2001, 01:21 AM

Hi,

To test it create a script with those lines and just run it

.
If you want it at the bootup add that script in the beginning of the /etc/rc.d/rc.local file.

If you have questions on how to create an extensive firewall you might want to check out http://netfilter.samba.org/unreliabl...WTO/index.html.

Good luck.

krquinby · 09-24-2001, 07:27 PM

This is a GUI to help you set up a firewall that uses IPTables. There is a wizard that will help you get started with the policy. There is an option to help you with masquerading as well.