[uClinux-dev] Network problems (I want to connect my host computer to uCsimm)

Eric Bosch (Fourtress) eric.bosch at fourtress.nl
Wed Apr 3 07:31:27 EST 2002

Thanks Heiko for your answer,

The output of the route -n command is:

Destination    Gateway    Genmask        Flags Metric    Ref Use  Iface    U    0        0    0    eth0        U    0        0    0    lo

My client is a uc68EZ328 Microcontroller module and it has a serial and a
ethernet connection. I can't use this serial connection, because I set a
environment variable with the wrong value. Now is the serial port blocked
and so I must establish the ethernet connection to set the environment
variable with the right value. It is important for me to establish this
ethernet connection.

Ok, I have installed tcpdump and execute the command and it says:

tcpdump: listening on eth0

That is the only information I become from tcpdump, so my tcp/ip connection
isn't OK !

Do you have any suggestions or more entry's to solve this problem?

I hope that you can help me?

Thanks, Eric

-----Oorspronkelijk bericht-----
Van: owner-uclinux-dev at uclinux.org
[mailto:owner-uclinux-dev at uclinux.org]Namens Heiko Degenhardt
Verzonden: woensdag 3 april 2002 12:49
Aan: Uclinux-Dev at Uclinux. Org
Onderwerp: Re: [uClinux-dev] Network problems (I want to connect my host
computer to uCsimm)

Hi Eric,

* On Wed, Apr 03, 2002 at 10:38:15AM +0200, Eric Bosch (Fourtress) wrote:
> I want to make a NFS connection with my 68EZ328 board, but I can't ping
> My computer has a crossover patch cable and a 3COM 3x59x network card.

The cable is ok? You have tested it with another pc?

> operating system is Linux Mandrake 8.1. (I can't use the serial
> because I set up a wrong environment variable in the uCsimm, so I must
> connect by ethernet!)

Ok. But has has nothing to do with NFS, imho.
You just need a working tcp/ip connection, that means ping
has to work, and then you can use telnet to connect.
But we can look after the NFS problem, if you want:

> The IP-address of the target is
> The IP-address of the host computer is
> The content of the /etc/exports file is:
>  /home/eric/uclinux

That should be enaugh. Here (on my SuSE 7.2 box) I have:
/home/hede/uClinux \

> The content of the /etc/hosts file is:
>    localhost.localdomain    localhost
>   uclinux.localdomain      uClinux
> #loopback address
>       localhost.localdomain    localhost

That seems to be ok, but should have no effekt on NFS
(because you give the IPs in /etc/exports).

> The content of the /etc/hosts.allow file is:
> ...
> The content of the /etc/hosts.deny file is:

I don't use any of that files. May be you should try
it without them at first...

> portmap:ALL

Imho this would deny every host that tries to use
your portmapper. That's imho not what you want.

Ok. But you problem seems to be the basic tcp/ip setup.

> When I execute the command ifconfig eth0 the following information
> eth0    Link endcap: Ethernet    HWaddr    00:04:76:26:91:12
>         inet addr:   Bcast: Mask:
>         UP BROADCAST RUNNING 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:100
>            ...
>            ...

Your client is running? It has his correct ip and netmask

> When I try to ping (ping the target from the host computer,
> the following message appears:
> Destination Host Unreachable

Could you please give me the output of the command
"route -n" on your host computer?
Could you install tcpdump, and see what is happening
on the interface? For me it looks as if your client
isn't set up correctly for tcp/ip.

As I said: You need ping to work to get the opportunity
to log in (for instance with telnet). To get ping both
sides have to be set up correct. You don't need NFS in
that stage, imho.

If you have more questions, please let me know.

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