[CLUG] Linux gateway

[Kevin Philp]

To make it even easier: I have Mandrake 9.0 installed on my gateway which runs 
masquerading and nat out of the box, we have a mix of windows and linux 
workstations. The gateway masqurerades everyones internet connect with the 
following little script for setting up nat

iptables -A INPUT -i ppp0 -m state --state NEW,INVALID -j DROP
iptables -A FORWARD -i ppp0 -m state --state NEW,INVALID -j DROP
iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE
echo 1 > /proc/sys/net/ipv4/ip_forward

I got the little script from the Linux 2.4 NAT HOWTO at:

http://netfilter.samba.org/unreliable-guides

We added the forward and input drop lines at the same time it blocks any 
baddies trying to get in.

Kevin.


On Sat 01 Feb 2003 18:58, David Dorgan wrote:
 > Most enjoyable pints. But back to business... anyone got any pointers to
 > well-written HOWTO's on setting up a Linux gateway? It would be nice if it
 > was an ISDN gateway on a Red Hat box being accessed by a Windows client, 
but
 > hey, I'm not fussy. :)
 
 Not being smart, but you could setup an openbsd NAT gateway
 with funky nat and filtering in about 30 minutes,
 including the install time.
 Just get the base, (you can do the ports later) 
 setup some basic pf and nat rules and you can do your
 port address translation or whatever else you want
 later, very easy syntax to learn.
 
 If you did want to go down the linux route, install debian,
 depending on what version you install, you may have to recompile
 the kernel with ip masq support.
 Anywho most of the information you require could
 be found at http://www.fifi.org/doc/iptables/html/NAT-HOWTO.html
 
 > adam
 David.
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