Hello everybody!

I have a big problem here: I just got a new PC and I wanted to configure it to do what my old one did: Work as an internet gateway for a winME PC. I've got 2 network cards in my Linux box, one goes to the DSL modem, the other one to a switch and then to the winME box. This worked perfectly in my old Linux box (debian), but on the new one, with a fresh Mepis install, I can neither ping my winME box from the Linux box, nor the other way round. Funny thing: If I switch on my old Linux box and connect it to the switch too, I can ping both Linux boxes from winME and winME from the old Linux box - not from the new one though.

Any idea which settings may be different on the new box than I had them on the old one? I'm starting to run out of ideas

Thanks a lot in advance,
-Wojtek

Is your firewall configured to accept pings? (try disabling it and see if it makes a difference)

Are your networks settings on both boxes exactly the same? (subnet masks the same)

I'm using firestarter and I have allowed all I can allow for the IP of the winME box. I also have internet connection sharing set to the device that's connected to the winME box. The subnet masks are exactly the same on all computers.

The funny thing is, even if it was a firewall, I should still be able to ping the winME box from Linux, shouldn't I? I was able to do so from the old Linux... and I'm able to ping anything on the internet, just not the winME box on the intranet

Is your ME box configured to acquire an IP address via DHCP? If so, then is your new linux box running dhcpd and is it configured correctly? Your probably getting an IP address from the old box which is why you can ping successfully when it is connected.

It also sounds like you have a routing problem on the new box. You can not ping the the ME box even when the old box is connected because it's default might be using the other network interface. Are you able to access the internet?

Unfortunately, it can't be DHCP: My old Linux box was 192.168.10.1, winME 192.168.10.2. I set the new Linux box to 192.168.10.1, that didn't work. When I switched my old box back on (so that all three computers were connected), I kept the new boxes' IP as 10.1, winME stayed 10.2, and I switched the old box to 10.5 - an IP I hadn't ever used before. Still, it worked. When I switched off the old box and rebooted the other two computers, the connection stopped working.

I can access the internet from both Linux boxes perfectly well (eth0 is for internet, eth1 is 192.168.10.1).

I'm really running out of ideas here Especially that now, without changing any configurations on my old box or on the winME computer, I have stopped being able to ping the winME box from the old Linux. I still can ping the old Linux from winME though, and Internet sharing over the old box works.

Wait, I have a theory. Too many computers connected to each other produce malvolent artificial intelligence and they're planning on overthrowing me. Have to correct this.

Ok, after a lot of trying around, I have managed to solve (well, kinda...) the problem.

It works if I have only eth1 configured to 192.168.10.1 at startup, and then do the following:
ifconfig eth1 down
ifconfig eth0 up
pon dsl-provider
ifconfig eth1 up
firestarter &

This is the only order in which it works, if I mix up any of the steps, then I either won't get the winME box to see the Linux box, or I won't be able to ping anything on the internet. This has a very black magic feeling to it, so I'll investigate further once I have time. It's really not the satisfying kind of solution :/

I'll pop back in to post what the real reason behind all of this was once I figure it out.

Thanks to all of your help and your time!