• Hawkandspit

    Link up/down detection

    December 18, 2019 by Hawkandspit

    How can I tell whether my network link is up or down so I know when I can use it? Once the link is up, do I call netifapi_dhcp_start to get an address?

    The lwIP documentation is skeletal and does not really tell how to use it. I need something more like a user's guide, as well as the reference manual.

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  • Vampire199669


    November 15, 2019 by Vampire199669


    i want to make my STM32 board as client and create GET/POST request to my server running remotely using Ethernet present on the board.

    how to http get post request on a running server.

    i have got an lwip example which explains the process of making board as a server not a client.

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  • Dimonira

    Strange NETCONN Behavior

    September 9, 2019 by Dimonira

    There are two FreeRTOS tasks, each of which creates its own NETCONN object. In one task (the first one begins to execute) there are no oddities when creating a NETCONN object. And in the second task there is: the object returned by netconn_new contains the incorrect address of the pcb union - it seems to be back to front.

    I went step by step into the netconn_new_with_proto_and_callback function (it is called when netconn_new), the conn object is created absolutely normal in it:

    But in the next step, when its address returns to the function call point, the debugger shows the NETCONN object with the incorrect pcb address:

    Further, at the very first attempt to use, for example, p UdpConn-> pcb.udp-> loc al_ip, the processor goes into the hardwa…

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  • Shahrukhkk

    LWIP with NS3

    July 4, 2019 by Shahrukhkk


    I have a question regarding the integration of LWIP with Network simulator 3. If I have to run simulations of LWIP in NS3 (or some other simulator), how can that be possible?



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  • Ddlawrence

    Hi all.  I am working on a lwIP port to the Beaglebone Black bare-metal (no OS). 

    So far the stack seems to work with the echo server and http server. 

    I am working on a UDP server/client now.  I can send a single packet from one 'bone to another. 

    I cannot send a series of packets a few seconds apart.  Only the first one gets thru.  Nothing on the IP layer either. 

    I must be doing something wrong setting up PBUF or the PCB.

    I am running out of options, anyone have an idea?


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  • Kausiknathan

    Hi ,

    I have an Infineon Aurix TC299 board with an ethernet interface.

    Infineon gave us the MCAL librabry to run the basic ethernet demo application like Ping, RX and TX frames etc etc.

    This library demo app intializes the MAC and the PHY at 100MBps.

    Issue :

    For our application we need the LWIP 2.0.2 stack integarted to this Libraby and ensure we send and receive the packets with TCP header + IP header + MAC header + payload format with the unit on the other side of our ethernet interface.

    This is a Non-OS board, so i intergarted the Lwip 2.0.2 stack with the library and made necessary changes as mentioned in the link provided below :

    We call the Lwip_init and Netif_add functions in the Ethernet Ini…

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  • Cuc0ach1ng


    I am developing a UDP application using lwip on a Zynq FPGA bare metal platform. My application sends Status packets using udp_sendto() to a PC host every 1s when the host is not responding. The packets are observed (on Wireshark) as being sent in the correct sequence and with the corrrect content and length. However, a packet doesn't appear on the network every 1s. 2 packets with same timestamp are sent on each 2s boundary. I believe by observing lwip debug prints that data is sent to the network every 1s but am not sure why the stalling of packets happens. Ay guidance is appreciated

    Thank you

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  • Doriano dotsys

    I'm using the LwIP ver. 1.3.2 ported by STMicroelectronics for the STM32F207 Microcontroller.

    My customers ask if this stack implemented the following RFC:

    -   link layer RFC: 826

    -   IPv4 network layer RFCs: 791, 894, 1042, 1122

    -   transport layer RFCs: 793, 813, 1122, 1191, 1323, 2012, 2581, 2988 There is someone can give a answer? Thanks in advanced.


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  • Johnwilliamhoffman

    We are using LWIP 1.3.2(as ported by TexasInstruments), IAR compiler targeting a stellaris MCU. The TI implementation uses a timer tick interrupt 100 times/sec to service the LWIP stack. No RTOS involved. Our application code also runs on this same timer tick interrupt so no concurrency issues in play.

    We implemented a webservice http client over tcp. Periodically(about 1-2 times per day), we miss ACKs in the application layer. Plain and simple, our tcp_sent callback does not get called. We have timers that expire if the ack is not seen. I have captured the WireShark trace and the ack is being transmitted. For some reason the lwip stack does not inform the application layer. I don’t know if the LWIP stack sees the ack or not.

    The odd thi…

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  • Bellphin

    TCP/IP Listen issue

    August 5, 2014 by Bellphin


    I use EVK1100 in AT32. In this project, we using RTOS+LWIP. 

    we have implemented the TCP/IP using default files. what problem we are facing in the

    project is that our TCP can listen the sockets only three times thereafter if we try to open the port it won't open. then we have to restart the system.

    So We want to know

    is any TCP/IP listen limitation in lwip?

    if any limitation are there how can we overcome the issue?

    Please anybody help for us?

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