Hallo, cc, Du meintest am 19.04.11: >>> Icmp4.cc:116: error: invalid use of undefined type `struct icmphdr' >>> Icmp4.cc:96: error: forward declaration of `struct icmphdr' >> <snip many repetitions on the problem> >>> Am I missing something? >> Some required header is not being found. > during ./configure wouldn't it tell me what header is missing and > not let me continue? No - no such message. Viele Gruesse! Helmut