Re: [lwip-users] TCP keeps re-transmitting but no ACK packet after SYN, SYN+ACK

[address@hidden]

Mohsin wrote:
> One more thing is that with exactly same IP configurations, webserver 
> code and same PC & device, webserver is working for one of my previous 
> backup codes (stable released LWIP 1.4.1 and not git head updated). 
> So, I guess there may be some change in the functionality of 
> tcp.c/tcp_in.c/tcp_out.c in current git head because of which my 
> application is not working.

Looking at the traces, all TCP packets sent by your device seem to have 
invalid *IP* checksums (where ICMP/IPv4 packets are OK). Since the TCP 
packets might well be pbuf chains while the ping-reply packets are 
(almost) surely single-pbuf-packets, I suspect a free-after-use issue 
somewhere in your port/driver setup.

Simon