Yes, thats what i read ;)
Now i solved the problem, i think these are the headers you need to include:
#include <arpa/inet.h>
#include <netinet/in_systm.h>
#include <netinet/tcp.h>
#include <netinet/in.h>
#include <netinet/ip.h>
but don´t change the order .... or you´ll get awful...