I repeat:
Quote:
Originally Posted by
Corona688
Do their MAC addresses at least show up in your ARP tables when they try to ping each other?
arp is a lower level of communication than most firewalls and can communicate even on a severely mis-configured network. When you try and do any sort of communication between hosts, whether they succeed or not they should at least get each other's MAC addresses in their ARP tables. If they don't even see each other on ARP, I suspect a hardware or cable issue.
If you don't know how to check ARP,
/sbin/arp -n.