OK I bought a managed switch, so I can now monitor the traffic on my network correctly. I set up the port mirroring function, to forward all traffic from the ethernet port the uC is connected, to the port that my PC is connected. I started wireshark but the problems persist.
First my code starts LWIP, the MAC controller and sets a static IP with no problems. Then my code enters a loop and tries a DNS query. Here the fancy staff starts. The first calls to dns_gethostbyname do not produce any traffic (yes I properly wait for the callback function to check the result, before the next call). After continuing to call this function, I finally see traffic in wireshark after app. 30 seconds. I can see an apparently normal DNS packet being sent but there is no response from the server. Then I tried to provide directly the IP of the server, (effectively I stopped using the DNS functionality), and tried to directly connect to an NTP server (using UDP of course). Again the same sumptoms. udp_send returns ERR_OK, but no traffic at the network. After app. 30 seconds I see the packets being sent but again absolutelly no response from the server. Keep in mind that I can ping my device normally, that I tried many servers (which are proved to work, testing from my PC), that I double checked our firewall (and that everything works OK from my PC). Also note that these problems exist only when I try to connect to an external (to my LAN) server. Trying to connect to a local server works normally. *Fotis Panagiotopoulos* *--* *AMCO S.A.* 25 Amfiaraou st. PO 10442, Athens, Greece Tel: +30 210 5907000 ext. -34 <%2B30%20210%205907000%20ext.%20-36> | Fax: +30 210 5912711 e-mail: [email protected] | web: http://www.amco.gr On Mon, Aug 1, 2016 at 9:22 PM, [email protected] <[email protected]> wrote: > Fotis Panagiotopoulos wrote: > >> I am asking for the brand/model number of the one that you are >> successfully using, to search for a new or used one. As you can image >> buying lots of switches in the hope that randomly one of them will have >> this functionality, is not an good idea :) >> > > You don't have to buy randomly, just look for a switch that supports "port > mirroring". These should be available from around ~100 EUR or USD... > > The more professional tool for monitoring would be an ethernet tap, which > has two ports that work like a repeater and forwards both RX sides to a 3rd > port (e.g. ETH or USB) to monitor via wireshark. > > If you want a cheaper solution, grab two network cards for your PC and > build your own passive tap (e.g. like this: http://www.securityforrealpeop > le.com/2014/09/how-to-build-10-network-tap.html). You'll have to monitor > every side on its own (using wireshark), but you can mix 2 pcaps into one > later if you prefer. Mixing is done via timestamps, so using 2 same cards > (which are NOT USB) should give the best results. > (ATTENTION: as this is passive and you attach a 2nd ETH receiver to one > cable, using very short cables is recommended - and worked well for me once > I tried!) > > Simon > > > _______________________________________________ > lwip-users mailing list > [email protected] > https://lists.nongnu.org/mailman/listinfo/lwip-users >
_______________________________________________ lwip-users mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/lwip-users
