Question

1

Impossible to ping when activating second network card

rated 0 times [ 1] [ 0] / answers: 1 / hits: 2495 / 2 Years ago, thu, september 15, 2022, 10:24:18

I'm new to Linux, trying to get a Clonezilla server up.
I'm really bad at understanding how my network should be configured.
eth1 is the card for internet access, behind a proxy (192.168.41.5:80)
eth2 is the card for deploying, connected to a router.

When eth2 is running, I can't seem to connect to the internet as it automatically try to use eth2 for everything (Firefox, ping, apt-get). Why is that?

Running Ubuntu 13.4

eth1      Link encap:Ethernet  HWaddr 00:04:76:14:52:9a  

          inet addr:192.168.12.2  Bcast:192.168.12.255  Mask:255.255.255.0

          inet6 addr: fe80::204:76ff:fe14:529a/64 Scope:Link

          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

          RX packets:1821 errors:0 dropped:137 overruns:1 frame:0

          TX packets:319 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:1000 

          RX bytes:214123 (214.1 KB)  TX bytes:54667 (54.6 KB)

          Interrupt:16 Base address:0xa000



eth2      Link encap:Ethernet  HWaddr 00:25:64:e7:2b:e3  

          inet addr:192.168.200.1  Bcast:192.168.200.255  Mask:255.255.255.0

          inet6 addr: fe80::225:64ff:fee7:2be3/64 Scope:Link

          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

          RX packets:0 errors:0 dropped:0 overruns:0 frame:0

          TX packets:6 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:1000 

          RX bytes:0 (0.0 B)  TX bytes:1004 (1.0 KB)

          Interrupt:16



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:65536  Metric:1

          RX packets:1115 errors:0 dropped:0 overruns:0 frame:0

          TX packets:1115 errors:0 dropped:0 overruns:0 carrier:0

         collisions:0 txqueuelen:0 

         RX bytes:85036 (85.0 KB)  TX bytes:85036 (85.0 KB)

My etc/network/interfaces:

auto lo

iface lo inet loopback



auto eth1

iface eth1 inet static

address 192.168.12.2

netmask 255.255.255.0

gateway 192.168.12.213



auto eth2

iface eth2 inet static

address 192.168.200.1

netmask 255.255.255.0

Ps: I'm connected in ssh (what a great invention) into 192.168.12.2 and it works (even if I can't ping my proxy)
Ps2: Sorry if it's a stupid question, "Linux" was just a fancy word for me not so long ago.

Have a good day :)

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answered 2 Years ago tionpromoti · Accepted Answer

You should be able to use the command ifmetric to set the metrics for each interface. The lower the metric the more "preferred" it is.

It is not included by default, but you can add it with sudo apt-get install ifmetric.

Then use ifmetric interface value to set the metric.

So to make eth1 "preferred" set its metric to 0, or set eth2's metric to 2 or higher.

To give credit were it's due, I found the answer here:

------------------------------------------------------------------------------------------------

Also, from the Debian Documents pages:

5.6.2. The ifmetric package

The ifmetric package enables us to manipulate metrics of routes a posteriori even for DHCP.

The following sets the eth0 interface to be preferred over the wlan0 interface.

Install the ifmetric package.

Add an option line with "metric 0" just below the "iface eth0 inet dhcp" line.

Add an option line with "metric 1" just below the "iface wlan0 inet dhcp" line.

The metric 0 means the highest priority route and is the default one. The larger metric value means lower priority routes. The IP address of the active interface with the lowest metric value becomes the originating one. See ifmetric(8).