Re: [lwip-users] lwIP Connection Initiation Issue

[Sergio R. Caprile]

You forgot to include your device address. If it is 192.168.1.x it is
fine (unless it coincides with any other device in the network...)

The error callback is called when the connection request is rejected or
lwIP gets tired of waiting for an answer. Do you see the SYN in
wireshark or equivalent ? (I believe you say you don't)
The timeout mechanism requires a timing source, pings are answered on
the fly. In fact, most TCP behavior relies on timers. Do you provide
your time source ?
However, the SYN should be able to get out... If SYN is not coming out,
then you are preventing the driver from running, perhaps one of the
locks is not correct.
You seem to have a broken port.
Though you are calling RAW API functions, you have an OS underneath. Are
you running in NO_SYS=1 or NO_SYS=0 ?
All calls to RAW API functions must be on the same thread that calls the
lwIP core.

Make sure you read and understand this:
https://www.nongnu.org/lwip/2_1_x/group__lwip.html
https://www.nongnu.org/lwip/2_1_x/pitfalls.html