How to know a network issue

[maheshgupta024]

Hi everyone, I have to make some descision for my project. I have some devices placed in the network. I shall send some commands and they respond to the comands. Now if they doesn't respond i treat as communication failure.
Now I know my device is working perfectly and the problem is with network. How would I make sure its the problem with the network but not with my device.

Can anyone guide to make some solution.
Thanks

[Irithori]

You could use tcpdump on the sender to trace, what really is sent and returns.
Also, if that device is unix based, then running tcpdump there also makes sense.

Did you check for errors with dmesg and ifconfig?
Are the connection parameters ok? 100mbit/s fullduplex or 1gbit/s fullduplex. Check with mii-tool or dmesg.

I also wouldnt rule out that device (btw: what is it?):
Maybe it has some low timeouts, that cant be met by your (busy?) network.
Or something simple like wrong gateway, netmask or dns?

[Kloschüssel]

How do you know that the device works perfectly if it doesn't respond?