I am setting up a network monitoring server with 9 network ports. I have installed two D-Link DFE 580TX four port network cards and I also have a built in port on the motherboard. I am running Linux Gentoo 2.6.8 and have the latest sundance driver installed, for the two D-link cards.

The problem is that I can't both cards working properly. I can can assign an IP to each port using dhcp. The problem is that I can only get five of the nine available port to work properly (ping outside network), being two ports off each card and the on-board one. I have fully tested the cards and the same problem occurs. I have tested each card by install one of them and then installing two single port network cards in the other two pci slots, giving me six ports in total but the same problem occurs. Only five of the six ports will work properly.

Is this problem related to the OS in that it limits the machine to only be able to support five network ports at a time or could it be some other problem? I have no other solution to this and can only assume that its an limitation of the OS. Is there some sort of variable that controls this attribute and can it be changed?

Any suggestions would be helpful.