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-   -   only one out of two network interfaces working (https://www.linuxquestions.org/questions/linux-networking-3/only-one-out-of-two-network-interfaces-working-643870/)

ernesto_cgf 05-21-2008 03:28 PM
only one out of two network interfaces working
 
I recently installed a Ubuntu 8.04 server in a computer with two phisical network cards. During the installation process the installer asked me which of these two interfaces should be used as primary and he refered to them as eth0 (a 3Com) and eth1 (a Realtek). I chose the 3Com eth0 to be used as the primary network interface.

This is my first time trying to set up a linux box with two network interfaces.

I assumed that having detected both interfaces, then both of them would be configured somewhow, at least with DHCP. But after the installation ended I only have one network interface configured. I go to /etc/network/interfaces and there's only the eth0 (fixed IP address) and the loopback configuration. No eth1.

This is the original /etc/network/interfaces file

Code:
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet static
    address 172.16.5.5
    netmask 255.255.0.0
    network 172.16.0.0
    broadcast 172.16.255.255
    gateway 172.16.5.82
And this is what I added by hand to try to see if I could get eth1 working

Code:
# The secondary network interface
auto eth1
iface eth1 inet static
    address 192.168.2.7
    netmask 255.255.255.0
    network 192.168.2.0
    broadcast 192.168.2.255
    gateway 192.168.2.2
But when I restart networking this is what I get

Code:
$ sudo /etc/init.d/networking restart
* Reconfiguring network interfaces...                                                                                                      SIOCSIFFLAGS: Invalid argument
SIOCSIFFLAGS: Invalid argument
SIOCSIFFLAGS: Invalid argument
Failed to bring up eth1.
I suspected that the secondary interface was not being physically recognized as a hardware component, but then why did the installer actually asked me for the primary interface? That means the it was able to determine that there were two network interfaces, isn't it? What's happening here?

Before you ask, this is the output of the command ifconfig -a

Code:
eth0      Link encap:Ethernet  HWaddr 00:01:02:05:f2:a0
          inet addr:172.16.5.5  Bcast:172.16.255.255  Mask:255.255.0.0
          inet6 addr: fe80::201:2ff:fe05:f2a0/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:394371 errors:0 dropped:0 overruns:31 frame:0
          TX packets:156982 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:187449172 (178.7 MB)  TX bytes:43155042 (41.1 MB)
          Interrupt:16 Base address:0x8800

eth1      Link encap:Ethernet  HWaddr ff:ff:ff:ff:ff:ff
          inet addr:192.168.2.7  Bcast:192.168.2.255  Mask:255.255.255.0
          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:17 Base address:0xec00

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:364 errors:0 dropped:0 overruns:0 frame:0
          TX packets:364 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:28739 (28.0 KB)  TX bytes:28739 (28.0 KB)
Note the invalid hardware address of eth1.

ernesto_cgf 05-21-2008 03:40 PM
Sorry,

I found the answer shortly after I posted this. There was a IRQ conflict between the two network cards. I went to the server's BIOS and changed the IRQ of the secondary card and everything works fine now. Thanks anyway.

This is where I found this information that allowed me to solve this: http://linuxmafia.com/faq/VALinux-kb...ags-error.html

What it says is the following:

Quote:
Q: Ethernet networking is not working. I get the error message:

"SIOCSIFFLAGS: Try again"

from ifconfig.

A: This usually indicates a hardware conflict with your ethernet controller. Run "ifconfig -a" and check the IRQ and I/O addresses used by the controller. Also, look at the contents of the files /proc/interrupts and /proc/pci to determine what IRQ and I/O addresses are in use on your system. Many ethernet and SCSI drivers cannot share interrupts under Linux. Your system most likely has an IRQ conflict.

To fix IRQ conflicts on PCI bus systems, you can often go into the motherboard BIOS setup and mark the conflicting IRQ as "Used by an ISA Device". This will force the motherboard to reassign the IRQ, often eliminating the conflict.

angel115 05-21-2008 03:46 PM
Hello Ernesto_cgf,


Well I don't form where does this issue is coming from, but I notice that the MAC address of your eth1 is not correct. :scratch:

What happen when you try to wake up the eth1 manually? (as follow)
Code:
ifconfig eth1 up 192.168.2.7  netmask 255.255.255.0
did you get any error message?

Regards,
Angel


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