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Unable to ping Linux eth0 from GNS router- Please Help
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Author:  dmenon [ Wed Sep 04, 2013 10:43 am ]
Post subject:  Unable to ping Linux eth0 from GNS router- Please Help

Hi,

I am trying a simple setup...as attached..and i am unable to ping to my eth0 in mu laptop running ubuntu 11.10.

I have configured the f0/0 in my router to 192.168.10.1 255.255.255.0
I have added a default route of " ip route 0.0.0.0 0.0.0.0 fa0/0" so that i t may divert all unknown routes through fa0/0.

the eth 0 in my ubuntu laptop is configured at 192.168.10.2 255.255.255.0 and up

the cloud is connected to nio_linux_eth:eth0:

i am not able to ping from R2(router in GNS) to Laptop eth0 or vice versa!! where Have i gone wrong.

Can anyone please help me fix this..?

Also i am not able to set up static routes. is that normal?
If i type ip route 192.168.10.0 255.255.255.0 fa0/0 it takes it but i dont see any route when i type sh ip route.! strange!

Attachments:
GNSscreenst.png
GNSscreenst.png [ 96.47 KiB | Viewed 6767 times ]

Author:  claydon_dan [ Wed Sep 04, 2013 12:35 pm ]
Post subject:  Re: Unable to ping Linux eth0 from GNS router- Please Help

Under linux you cannot ping the ethernet interface of the host machine. This is mentioned in the FAQ post

FAQ wrote:
On Linux / Unix / OS X, when I bridge a router or switch interface to my local host I can’t ping it from my host. But this works on Windows? What gives?

This does generally work on Windows (depending on your network card) but not on Linux / Unix. Most likely this is due to differences between libpcap and Winpcap, and the differences in the network stacks on Unix / Windows (e.g. NDIS). However you should be able to ping your bridged interfaces from other systems on the bridged network. If this does not work on Windows for your particular NIC, try creating a Windows loopback adapter and bridging to that. On Linux you can use a tap interface and the NIO_tap (available from a cloud). OS X you can install tun/tap drivers.


If you need to access the host machine, you can create a tap interface. You can find details on how to do this here.

If you don't to access the internet, you won't need to create the bridge.

Author:  dmenon [ Thu Sep 05, 2013 10:05 am ]
Post subject:  Re: Unable to ping Linux eth0 from GNS router- Please Help

Hi Claydon,

Thanks much for replying. I did try creating a tap0 interface assigning that to the cloud but I still was unable to ping.

Also can we create static routes on GNS? I for some reason am not able to.

Regards,
Menon

Author:  claydon_dan [ Thu Sep 05, 2013 11:11 am ]
Post subject:  Re: Unable to ping Linux eth0 from GNS router- Please Help

dmenon wrote:
I did try creating a tap0 interface assigning that to the cloud but I still was unable to ping.

Hmm, I would need to see bit more info to debug. But for starters can you see the tap interface, by running ifconfig (or ifconfig -a) in a terminal window. If it appears in the second but the first you need to bring the tap interface up.
Code:
sudo ifconfig tap0 up

dmenon wrote:
Also can we create static routes on GNS? I for some reason am not able to.

Yes, you certainly can create static routes in GNS3, you have access to pretty much everything tthe Cisco IOS offers.

Author:  dmenon [ Fri Sep 06, 2013 10:57 am ]
Post subject:  Re: Unable to ping Linux eth0 from GNS router- Please Help

Thanks Claydon,

I tried to recreate the same on my windows laptop referring this video below and as mentioned in the video my router was able to receive an ip address assigned by the dhcp server but i would not be able to ping to my laptops nic directly. It seems it bypasses the NIC.

http://www.youtube.com/watch?v=tgJgUyja0XU

My Tap0 interface was up and i could see it in both ifconfig as well as ifconfig --a.

I am not able to create static routes on my routers. Even after i do i am not able to see them when i do a show ip route!!
Any reason why i am not able to see em..?


Thanks,
Menon

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