Home / ubuntu / Questions / 99411
Accepted
One Zero
Asked: 2012-01-29 14:28:52 +0800 CST

how to ping & use specific network card

  • 772

i have 3 network cards , 1 Lan (wired) , 1 wireless network card & 1 is wireless usb

how do i ping from specific network card ?

& how do i use specific network card for specific application

example 

i want to ping google from wlan0

example for specific application

i want to use firefox or transmission from wan1

UPDATED

Lan ip 192.168.0.2 > Working Properly enter image description here

Wlan1 ip 192.168.0.3

enter image description here

pin -I wlan1 google.com

UPDATE

Try pasting the output of route -n and/or ip route. Seems to me that the wlan1 interface hasn't a valid gateway configured. –@MrShunz

one@onezero:~$ route -n 
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         192.168.0.1     0.0.0.0         UG    0      0        0 eth0
169.254.0.0     0.0.0.0         255.255.0.0     U     1000   0        0 eth0
172.16.221.0    0.0.0.0         255.255.255.0   U     0      0        0 vmnet8
192.168.0.0     0.0.0.0         255.255.255.0   U     1      0        0 eth0
192.168.0.0     0.0.0.0         255.255.255.0   U     2      0        0 wlan1
192.168.48.0    0.0.0.0         255.255.255.0   U     0      0        0 vmnet1
one@onezero:~$ ip route
default via 192.168.0.1 dev eth0  proto static 
169.254.0.0/16 dev eth0  scope link  metric 1000 
172.16.221.0/24 dev vmnet8  proto kernel  scope link  src 172.16.221.1 
192.168.0.0/24 dev eth0  proto kernel  scope link  src 192.168.0.2  metric 1 
192.168.0.0/24 dev wlan1  proto kernel  scope link  src 192.168.0.3  metric 2 
192.168.48.0/24 dev vmnet1  proto kernel  scope link  src 192.168.48.1
11.10

1 Answers

  1. Best Answer

    ping has a specific switch to set source interface: -I. As found in the manpage:

     -I interface address
          Set source address to specified interface address. Argument may be  numeric  
          IP  address  or  name  of device.
          When pinging IPv6 link-local address this option is required.

    As an example

    $ ping -I wlan0 8.8.8.8

    ping 8.8.8.8 through wlan0 interface.

    Forcing an interface for a specific application needs some more work. You can find a solution in this superuser.com question and in this article linked in the answer.

    UPDATE

    The methods i exposed in this answer show how to force ping to use a specific interface. And links to some articles on how to force a generic program to use a specific interface.

    Now, for all this to work, you have to configure some "advanced" routing. As you can see from the output of route -n you have multiple networks, but only ONE gateway to the Internet. That is good, as multiple gateway routing is quite an advanced topic and somewhat difficult to handle well.

    This goes beyond what you asked in the original question. I suggest you to post a new question here or on Server Fault asking how to configure and manage multiple internet gateways on multiple network interfaces.

    Or, better yet, try googling it ;) Also check the LARTC site for advanced linux routing configurations.

    • 11