Router without firewall

edman007 · 09-03-2006, 09:08 PM

how do i setup a box to act as a router (forward traffic from eth1 to/from eth0), so far all i have found are things that make a firewall, but my router is already behind a firewall and is on a trusted network, all i want is for it to act as a wifi bridge, i will control wifi access with stuff like WPA so i just want it to route data between two trusted networks, no firewalling at all

camh · 09-04-2006, 01:29 AM

iptables will do the trick. Something like:

Code:

echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -A FORWARD -i SRCIF -o DSTIF -j ACCEPT
iptables -A FORWARD -i DSTIF -o SRCIF -m state --state ESTABLISHED,RELATED -j ACCEPT

edman007 · 09-04-2006, 05:23 PM

ok, i tried that and it doesn't work, these are the exact commands i used (i'm on slack, so i used the startup script to do the ip_forward)

Code:

iptables -A FORWARD -i ath0 -o eth0 -j ACCEPT
iptables -A FORWARD -i eth0 -o ath0 -m state --state ESTABLISHED,RELATED -j ACCEPT

ath0 is my wifi in AP mode, eth0 is my wired connection connected to my router/firewall, ath0 has the ip 192.168.2.1, eth0 has 192.168.1.25, my router/firewall is 192.168.1.1

my laptop is on wifi has the ip 192.168.2.2 with the router set to 192.168.2.1, after doing the ip_forward stuff i can ping 192.168.1.25(eth0) and 192.168.2.1(ath0) but i can't ping 192.168.1.1(router/firewall)

i've been looking into bridging with brctl but so far i have had little success

edman007 · 09-04-2006, 06:21 PM

ok, i got it working with brctl now, i moved the laptop to have an ip of 192.168.1.20 and gave it a router of 192.168.1.1(the real router/firewall)

then i took both ips off my box acting as an ap

Code:

ifconfig ath0 0.0.0.0
ifconfig eth0 0.0.0.0

then i put the wifi in promisic mode

Code:

ifconfig ath0 0.0.0.0 promisc

then i created a bridge containing both interfaces

Code:

brctl addbr br0
brctl addif br0 ath0
brctl addif br0 eth0

brought the bridge up using my old IP

Code:

ifconfig br0 192.168.1.25 up

and added my gateway back to the routing tables

Code:

route add default gw 192.168.1.1

archtoad6 · 09-05-2006, 05:13 PM

Before you tried bridging, did ever execute the recommended:

Code:

echo 1 > /proc/sys/net/ipv4/ip_forward

?

None of the iptables "FORWARD" commands will do anything if forwarding is not also turned on.