Why changing value of SO_RCVBUF doesn't work?

Question

I\'m making a program which create a RAW socket in order to read all traffic. Between the call of socket() and recvfrom() (last one is in a loop to get out all packets from

Answer 1

The level argument to setsockopt should be SOL_SOCKET, not 0:

int a = 65535;
if (setsockopt(sockfd, SOL_SOCKET, SO_RCVBUF, &a, sizeof(int)) == -1) {
    fprintf(stderr, "Error setting socket opts: %s\n", strerror(errno));
}