Hello, I have bothered this list before with a little project I am working on, so here goes again. I have 3 hosts: a client, a primary and a backup server, all on a HUB, so everybody hears everybody else's traffic. The primary and the backup have the same IPs AND the same MACs. The backup has ifconfig eth0 -arp ifconfig eth0 promisc , meaning I have disabled arp broadcasting and I ve put its interface in promisc mode. I am using iptables in the backup to redirect all traffic going in or out of its NIC to a QUEUE target, and these packets get processed by a script of my that is suppossed to do smthing. So, say I do a telnet from client to primary(and the backup, since they got the same IP). The primary will do the TCP handshake OK, and the backup will get fucked up, sending RST tcp packets. What SHOULD traverce the firewall (and hence the QUEUE target) on the backup is: -the clients SYN packet going in -the primary SYN/ACK packet going in -the backup SYN/ACK going out -the client ACK going in then the backup server would see the wrong ACK that came in and get fucked up(send an RST?). But the packets that come from the primary server(which has the same IP/MAC) NEVER go in the backups QUEUE. Why is that?? I dont grab them at the QUEUE target, but I can see them crossing if I use ethereal!
