Ross, The diagram really helps. My guess is what you need to do is put a second address on eth0, and then differentiate your packets according to which address they have arrived at on the Linux box - for example, 10.4.44.11 or 10.4.44.12. And yeah, there should be a way to do it by MAC address, but this should be simpler. Whit On Tue, Dec 04, 2001 at 02:11:37PM -0800, Ross Simpson wrote: > First off, here's a diagram: > > > I N T E R N E T > / \ > ------------- ------------- > | 10.4.44.1 | | 10.4.44.2 | > | lucent | | speed | > ------------- ------------- > port-fw 80 port-fw 80 > \ / > \ / > \ / > ----------- > | hub | > ----------- > | > | > | > | > eth0 > -------------- > | 10.4.44.11 | > | linux | > -------------- > > I have a default gateway as specified in /etc/sysconfig/network: > GATEWAYDEV=eth0 > GATEWAY=10.4.44.1 > > I ran the below commands to use multiple default gateways. > > So here's what I would _like_ to see: > Traffic coming to the box from the internal network uses the default route > from /etc/sysconfig/network. > Traffic coming from the internet (from the 10.4.44.1 router, then > port-forwarded 10.4.44.11) should use 10.4.44.1 as the gateway to return the > packets to the client. > 10.4.44.2 should work identically to 10.4.44.1. > > Right now, traffic coming from the system default gateway works great. > Traffic coming from 10.4.44.2 gets to the system, however I would guess that > it's being sent back to 10.4.44.1 as it is the default gateway. > > As I'm watching a tcpdump, I see that packets are coming in with their > original (external) IP addresses, instead of the address of the router (I > was thinking that port forwarding temporarily changed the source IP of the > packet; apparently not). So the setup is not working because external IPs > don't match 10.4.44.1 or 10.4.44.2, and the system's default gateway is > used. > > So, I guess my question becomes: is there any way for linux to tell which > router the packet came from? Could it tell maybe by mac address? > > Thanks for the help! > Ross
