Re: [lwip-users] LPC1769 ethernet problem

[Fotis Panagiotopoulos]

No the ARP requests are send at the beginning of the transmission. As I stated the problem appears only when I try to access a server outside of my local network.

I coded LWIP to send some data through UDP. Before the UDP connection, as it is normal it decides that the traffic should be send to the router (I followed the code till here with my debugger), then it realises that it doesn't know the address of the router, and sends the ARP request, that however is never responded.

When the router responds to another ARP request, generated by another device on my network, LWIP knows the MAC and tries to send the UDP packet, again with no response. Obviously this will happen at a random time (the app 30 secs delay I mentioned above).

It seems that the router has something personal with my microcontroller...

Fotis Panagiotopoulos

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On Fri, Aug 12, 2016 at 9:40 PM, address@hidden <address@hidden> wrote:

Fotis Panagiotopoulos wrote:

As I see in wireshark, when my microcontroller sends an ARP request about my gateway it does not receive any response. It continues sending the same request for about 30 secs (the time I wasn't seeing any UDP traffic), and then it starts sending the UDP packet.

Sorry if I ask the wrong questions, but I haven't been monitoring this thread fully.

When are the ARP requests sent? In the middle of a transfer? Can you get us a pcap of that period? If it's in the middle of a transfer, it could well be that the ARP cache timed out and that there is some kind of bug in that handling for you. Which version if lwIP are you using again? (Again, sorry if I ask something already asked before...)

Simon

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