FC3 with kernel 2.6.11-1.27_FC3smp eth0 and eth1 as slaves to bond0. After 2 years of having the channel bonding setup all OK, something strange happened. Basically, I cannot ping any other hosts on the same subnet. What is more strange is that, if I run ethereal and capture packets in promiscuous mode, I can see ARP requests ( ONLY ) from other hosts, and the host replies back with the ARP response, etc... If I change the active slave from eth0 to eth1, then everything is working. If I change the active slave back to eth0 from eth1, then nothing is working ( apart from ARP packets ). mii-tool confirms that the link is up on both NICs.