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?