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

[Sergio R. Caprile]

> For ethernet packets, I'm claculating checksum in hardware but for TCP and
> IP, its is in software only.


>> My suggestions:
>> 1) Check for this
>>      #define CHECKSUM_GEN_IP                 1

>I checked above Macro in my opt.h and it is set to 1.

Then you have just found your problem.

If you are calculating IP checksums in hardware, you must not calculate them in lwIP.

Set 
#define CHECKSUM_GEN_IP                 0