[lwip-users] IP header checksum problem with lwip-1.4.1 on Win XP with winpcap

[Moldenhauer, Frank]

Hi,

I just compiled lwIP-1.4.1 with contrib-1.4.1 and WinPcap 4.1.2 on Win XP with 
MSVC. Ping worked well, but not httpd. I switched debug messages on 
(/contrib-1.4.1/ports/win32/include/lwipopts.h) and got 
tcp_input: packet discarded due to failing checksum
error messages, caused by tcp_in.c:
      LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packet discarded due to failing 
checksum 0x%04"X16_F"\n", ...
inet_checksum.c:  inet_chksum_pseudo()
I disabled checksum computation setting #define CHECKSUM_CHECK_TCP  0 in 
/lwip-1.4.1/src/include/lwip/opt.h and httpd seems to be ok (I get the 
index.html page).

Has anyone encountered the same problem or any idea what's wrong (transfer 
seems ok, error in IP header checksum computation)? 

Thanks

Frank