I have an interesting issue.
here is my setup up using ubuntu 8.04lts, 32bit server

Dell 2650 Server with 3 nics, all gig ports

ethtool -i eth0 (GB1 on Dell Server on-board)
driver: tg3
version: 3.86
firmware-version: 5703-v2.25a
bus-info: 0000:05:06.0


ethtool -i eth1 (In a PCI slot)
driver: e1000
version: 7.3.20-k2-NAPI
firmware-version: N/A
bus-info: 0000:01:08.0

ethtool -i eth2 (GB2 on Dell Server on board)
driver: tg3
version: 3.86
firmware-version: 5703-v2.25a
bus-info: 0000:05:08.0


NOW eth0 is connected into the main network and working fine ethtool provides the following information:

Settings for eth0:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Advertised auto-negotiation: Yes
Speed: 1000Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 1
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: g
Wake-on: d
Current message level: 0x000000ff (255)
Link detected: yes



ETH1 is not connected to anything and not being used(PCI slot)

ETH2 is uses a cross connect cable to connect to Netgear NV 4000 NAS which has a Gigabut port.

If I configure the /etc/network/interfaces file without eth2 configuration, and I run ethtool eth2 I get:
Settings for eth2:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Advertised auto-negotiation: Yes
Speed: Unknown! (0)
Duplex: Half
Port: Twisted Pair
PHYAD: 1
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: g
Wake-on: d
Current message level: 0x000000ff (255)
Link detected: yes


If I configure /etc/network/interfaces with ETH2 and assign an IP address I cannot connect to the NAS, and when I do ethtool eth2 I get:

Settings for eth2:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Advertised auto-negotiation: Yes
Speed: Unknown! (65535)
Duplex: Unknown! (255)
Port: Twisted Pair
PHYAD: 1
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: g
Wake-on: d
Current message level: 0x000000ff (255)
Link detected: no

PROBLEM:
It seems that when I activate the ETH2 interface in the /etc/network/interfaces file, ethtool no longer detects the link and I cannot ping my NAS.
I can ping myself 192.168.21.5 but not the NAS(see ip configuration below)

I have configured the interfaces file and rebooted the system, but still no resolve.


Here is the interfaces file as of my last reboot


#The loopback network interface
auto lo
iface lo inet loopback

#The primary network interface GB1 on board
auto eth0
iface eth0 inet static
address 10.130.0.227
netmask 255.255.255.0
network 10.130.0.0
broadcast 10.130.0.255
gateway 10.130.0.1

#The NAS interface GB2 onboard
auto eth2
iface eth2 inet static
address 192.168.21.5
netmask 255.255.255.0
network 192.168.21.0
broadcast 192.168.21.255

Any assistance would be great.

Also here is the dmesg log related to interfaces.

root@DM:/etc/network# dmesg | grep -i eth0
[ 136.594499] eth0: Tigon3 [partno(BCM95703A30) rev 1002 PHY(5703)] (PCIX:133MHz:64-bit) 10/100/1000Base-T Ethernet 00:0f:1f:6b:93:01
[ 136.594519] eth0: RXcsums[1] LinkChgREG[0] MIirq[0] ASF[0] WireSpeed[1] TSOcap[1]
[ 136.594525] eth0: dma_rwctrl[769c4000] dma_mask[64-bit]
[ 177.812362] tg3: eth0: Link is up at 1000 Mbps, full duplex.
[ 177.812367] tg3: eth0: Flow control is off for TX and off for RX.
[ 191.579873] eth0: no IPv6 routers present
root@DM:/etc/network# dmesg | grep -i eth1
[ 136.670396] eth1: Tigon3 [partno(BCM95703A30) rev 1002 PHY(5703)] (PCIX:133MHz:64-bit) 10/100/1000Base-T Ethernet 00:0f:1f:6b:93:02
[ 136.670408] eth1: RXcsums[1] LinkChgREG[0] MIirq[0] ASF[0] WireSpeed[1] TSOcap[1]
[ 136.670411] eth1: dma_rwctrl[769c4000] dma_mask[64-bit]
[ 174.288170] udev: renamed network interface eth1 to eth2
[ 174.578233] udev: renamed network interface eth2_rename to eth1
root@DM:/etc/network# dmesg | grep -i eth2
[ 137.212719] e1000: eth2: e1000_probe: Intel(R) PRO/1000 Network Connection
[ 174.288170] udev: renamed network interface eth1 to eth2
[ 174.578233] udev: renamed network interface eth2_rename to eth1

[ 174.288170] udev: renamed network interface eth1 to eth2
[ 174.578233] udev: renamed network interface eth2_rename to eth1

It strikes me that the onboard nics are being found first, and rather than have eth0 and eth2, udev renames them. Then the wrong options are applied to each. Can you fiddle things to eliminate this as an possibility?