turning ubuntu/linux into a router

fdelval · 08-06-2010, 02:31 AM

Hello all

i would like to know whats the minimal iptables config for turning my ubuntu box into a router

i just tryed this one and works:

echo "1" > /proc/sys/ipv4/ip_forwarding
and
sudo iptables -A POSTROUTING -t nat -j MASQUERADE
(default policies are ACCEPT)

Ok, now im wondering if i can remove that NAT policy, or if that is absolutely necessary

if so, what is the minimal rules i must set up in order to route¿

sem007 · 08-06-2010, 05:44 AM

What is your exact requirement to create linux router?

BTW below links give you idea.

https://help.ubuntu.com/community/In...nectionSharing

http://ubuntulinuxhowto.blogspot.com...be-router.html

fdelval · 08-06-2010, 06:15 AM

Quote:

Originally Posted by sem007

What is your exact requirement to create linux router?

BTW below links give you idea.

https://help.ubuntu.com/community/In...nectionSharing

http://ubuntulinuxhowto.blogspot.com...be-router.html

Hello sem007,
Well, i have deployed a handfull of firewall/routers, but always with a fixed config. It worked ok with a proxy, dhcpserver etc etc, but i have never understood WHY or HOW it worked.
With the last server i have started, i want to LEARN what am i doing, and thats why i want to know exactly which commands to what thing.
All manuals are "complete" but i want to try "incomplete" configs, and thats why im here, asking why i need that, and what i dont need...

sem007 · 08-06-2010, 06:41 AM

Quote:

Originally Posted by fdelval

Hello sem007,
Well, i have deployed a handfull of firewall/routers, but always with a fixed config. It worked ok with a proxy, dhcpserver etc etc, but i have never understood WHY or HOW it worked.
With the last server i have started, i want to LEARN what am i doing, and thats why i want to know exactly which commands to what thing.
All manuals are "complete" but i want to try "incomplete" configs, and thats why im here, asking why i need that, and what i dont need...

ok... i advise you to spend some time to read,learn and test iptables rules. look below link that will help to understand iptables rules. There is some tutorials links also available.

Iptables

HTH