Re: [lwip-users] LPC1769 ethernet problem

[Fotis Panagiotopoulos]

Yes the gateway is correctly set. I was expecting to see the traffic using the promiscuous mode of my adapter, as I am able to capture packets that their destination is other than my PC.

Running the server on the same PC is not an option, since as I stated everything works perfectly then. The problems start when I want to reach an external server.

Fotis Panagiotopoulos

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On Mon, Jul 25, 2016 at 7:37 PM, Chris Williams <address@hidden> wrote:

Quoting Fotis Panagiotopoulos <address@hidden>:

You talk about wireshark. If you are running wireshark on a PC, you will not see the attempt to connect to a remote server from your device. The switch or router you are using will not send any of that traffic to the PC unless you provide a special routing. I have a router that has a debug output that will copy all traffic to a debug port which I then monitor with the PC.

If you can run the server on the SAME PC as wireshark then you will see the traffic.

Alternatively, have you provided a gateway address? For routes external to the local network the gateway address is needed.

Does that explain anything?

Regards,

Chris.

Hi,

I am using LWIP 1.4.1 for a microcontroller project, based on the NXP
LPC1769 MCU. I do not use an RTOS and thus I am using the raw API.

I created the device drivers mostly based on the examples provided by NXP.

While a try any connection to my LAN, everything works perfect. However
each time I try to connect to a server external of my local network
(internet) LWIP does not generate any traffic at all, as seen by wireshark,
and all connection attemps fail.

I already have tried connecting to many different servers, which are
confirmed to operate correct, and I also tried the provided DNS module. I
tried both TCP and UDP connections and all fail with no traffic on my
network at all.

I double checked for any firewalls in my router or ISP, and everything
seems normal. I also tried in various different networks (2 DSL lines, and
through one 3G router), with the same outcome every time.

All addresses are double checked to be correct  (IP, gatway etc...).

One thing to note is that after hundrends of tries, randomly I achieved
connection with a DNS and an NTP server, with no apparent changes to my
code. Even in that cases after a few packets, the connection was again
dying requiring a restart of my app. A few tries later with no code changes
resulted again in the same problem.

Memory management is closely observed, there aren't any memory leaks, nor
my application runs out of memory.


Are there any ideas for this problem? I suspect my low-level driver, which
however operates very good in my local network. How are the packets
different when the destination is in a LAN vs WAN?

<http://www.amco.gr/>

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