I didn't send you the capture because there is nothing
special at all, just like lwip decided it is time call it off
Maybe the ACK was indeed lost, but lwIP should resend it after timeout as
you suggested (the tcp stack I used before does that), let me know if
there is a fix to it
thx
>>>>>>>>>
You haven't sent a packet capture of that case yet. My best guess
for
that is that the last ACK gets lost, and then both sides are waiting
for
the other. lwIP should probe the other end in that situation,
but the
code to do that was relatively recent (just before 1.3 I think) and
there may still be some issues with it.