hi all
i have 1 nic in my linux machine and i want to use it as a router

i have created an alias eth0:1

my eth0 is 10.10.1.1 255.255.255.0 (i wanna use this as dhcp as well)
my eth0:1 is 192.168.1.102 255.255.255.0 (my crappy router is 192.168.1.1)
how do i forward all traffic from eth0 through eth0:1

im going to try this and if succsefull a squid with QoS

thanks all

You probably need to allow forwarding (echo "1" > /proc/sys/net/ipv4/ip_forward)

What's the output of "route"

here is my route -n


Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
10.10.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 eth0
0.0.0.0 192.168.1.1 0.0.0.0 UG 100 0 0 eth0

and

route

Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.1.0 * 255.255.255.0 U 0 0 0 eth0
10.10.1.0 * 255.255.255.0 U 0 0 0 eth0
link-local * 255.255.0.0 U 1000 0 0 eth0
default 192.168.1.1 0.0.0.0 UG 100 0 0 eth0

So if you send traffic through this box on 10.10.1.1, what happens?

from my xp box if i setup ip on the same subnet with gw set to 10.10.1.1

i get nothing ndr
cant ping google by name or ip
i can ping 10.10.1.1

Did you set forwarding as per post #2?

I just ran a quick test and enabling forwarding plus adding the IP alias seems to work for me.

FYI - route from client
route on "router"
ifconfig on "router"
cat /proc/sys/net/ipv4/ip_forward
Running wireshark on "router" confirms traffic passing through.

How do you even wire a one-NIC router?

ok ill start again..
i have 1 imac g4 (ubuntu server, dhcp, dns, web, email) this only has one nic.

this is connected to my crappy di-624 router, i also have a desktop box and a few lappys.

what i want to do is have all lan traffic pass through the di-624 to the linux machine and then filtered it on the linux box. i also want to use it as a squid with qos.

i have created eth0:1 on a totally different subnet. i want eth0 for dhcp and eth0:1 for external(internet facing)

so here is my interfaces..

# The primary network interface
auto eth0
iface eth0 inet static
address 10.10.1.1
netmask 255.255.255.0
auto eth0:1
iface eth0:1 inet static
address 192.168.1.101
netmask 255.255.255.0
gateway 192.168.1.1

the 10. range is going to be the local subnet and the 192 range is the external to the router.

cat /proc/sys/net/ipv4/ip_forward = 1
but this changes back to 0 after reboot
here is my rotue on the linux machine
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.1.0 * 255.255.255.0 U 0 0 0 eth0
10.10.1.0 * 255.255.255.0 U 0 0 0 eth0
link-local * 255.255.0.0 U 1000 0 0 eth0
default 192.168.1.1 0.0.0.0 UG 100 0 0 eth0

now if i turn my dhcp router on the dlink off and the dhcp on my nix machine on it servers ips fine.
from my xp machine on the nix dhcp range.
ping 10.10.1.1 reply (nix eth0)
ping 192.168.1.101 reply (nix eth0:1)
ping 192.168.1.1 fail (dlink router)

so i can basically talk to the local network but not to my dlink..
so i cant pass traffic from 10.10.1.1 through the 192.168.1.101 to the dlink 192.168.1.1 internet facing address

i dont have any firewall on my nix machine yet... i was going to add that after i got the eth0 and eth0:1 talking properly

ipforward is 1