Programming

In attachment, is the code to test IP by ARP proxy. I always use it to test a IP already existing in my cluster.

Usage:
arp_func eth0 192.168.1.1

Enviroment:
IA64, RedHat AS3.0, 2.4.21-15.EL, gcc-3.2.3-34,
"gcc -o arp_func arp_func.c"

When the code below added before test_ip() in main(), program could receive ARP reply correctly:
fprintf(stdout, "anything");
or fprintf(stderr, "anything");
or getchar();
or fopen("anyfile", "anymode");

But, if the code above removed, recvfrom() fails and error is "Invalid argument".

I don't understand why the operations on other fds could affect the socket.

any dude can explain it? thanks in advance:-)