Quote Originally Posted by CapNemo
EDIT:
you're really fast *g*
i cannot connect it directly to the router (it's a cable mess already, and i cannot move the router or the box atm.. but all other machines using that switch (4 port) are working normally...
tried to use tcpdump, only message i see while trying to ping is "arp who-has 192.168.2.1 tell 192.168.2.x", does it need to know the routers mac address too?
i'm going to try ethereal now...
Please quit editing to add information, as I don't get any notification that there is more information posted that way. Just add a new post to the thread.

Also, please stop the 192.168.2.x stuff. This is where it really matters and I can't tell what is hapening when you make the changes to Xs. All 192.168 addresses are completely local and cannot be reached across the network, so there is no security issue here and no reason to hide local addresses.

ARP (address resolution protocol) is one of the things that you see when you sniff the wire. It seems that ARP is working if other pings are getting to you and back to you across the network, but since we have a situation that makes no sense here I don't want to just assume that. You should see different ARP packets. You will not see other systems respond to the router since you are on a switch rather than a hub (although you could see these packets with ethereal on the other system, there is a windows version as well as a linux version).

What will happen during ARP is an exchange of IP and MAC address information. This is how the system matches up IP to MAC addresses.

For that matter, have you tried to boot the Knoppix CD on any of the other systems? Is this problem local to this one PC, or does it exist when any PC tries to ping the router from Knoppix?