config problem with dual NIC mainboard

Hi,

I encounter a problem in network configuration for an Intel S3420GPV mainboard.
The board is equipped with two NIC's.
Logically they should work independent of each other, but I find that it is indeed not the case.

Here are the steps I've followed:

1. Before starting, all patch cables are disconnected.

2. Booting system with Slackware64-14.2 distribution (huge.s/bzImage + initrd.img).
The devices "eth0" (MAC xx:xx:xx:xx:xx:47) & "eth1" (MAC xx:xx:xx:xx:xx:46) are up.

3. At the root prompt, configure "eth1" with the command
Code:ifconfig -v eth1 aaa.bbb.ccc.29 broadcast aaa.bbb.ccc.255 netmask 255.255.255.0 Code:eth1 Link encap:Ethernet HWaddr xx:xx:xx:xx:xx:46
inet addr:aaa.bbb.ccc.29 Bcast:aaa.bbb.ccc.255 Mask:255.255.255.0
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
Interrupt:16 Memory:b1100000-b11200004. Connect system to network via the external connector corresponding to "eth1".
Ping from another node on the same subnet has no problem :
Code:PING aaa.bbb.ccc.29 (aaa.bbb.ccc.29): 56 data bytes
64 bytes from aaa.bbb.ccc.29: icmp_seq=0 ttl=64 time=0.372 ms5. Detach the patch cable from "eth1".

6. Configure "eth0" with the command
Code:ifconfig -v eth0 aaa.bbb.ccc.129 broadcast aaa.bbb.ccc.255 netmask 255.255.255.0 Code:eth0 Link encap:Ethernet HWaddr xx:xx:xx:xx:xx:47
inet addr:aaa.bbb.ccc.129 Bcast:aaa.bbb.ccc.255 Mask:255.255.255.0
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
Interrupt:16 Memory:b1100000-b11200007. Connect system to network via the external connector corresponding to "eth0".
Ping from another node on the same subnet fails :
Code:PING aaa.bbb.ccc.129 (aaa.bbb.ccc.129): 56 data bytes
--- aaa.bbb.ccc.129 ping statistics ---
158 packets transmitted, 0 packets received, 100% packet loss8. Detach cable from "eth0" and insert it to "eth1", then ping both IP's are successful.

The experiment has been repeated with the order of configuration reversed, the result is reversed accordingly.

It seems that only the interface configured first is functional, the functionality of the other interface is somehow bound to the first one.

I don't think this is normal, but can't find a fix from web search.

Could someone kindly help ?