netdetails.c

//program to give you the details of the network in which you are
#include<netinet/in.h>
#include<arpa/inet.h>
#include<unistd.h>
#include<netdb.h>
#include<stdio.h>
#include<stdlib.h>
int main(int argc, char *argv[])
{
char *host, **names, **addrs;
struct hostent *hostinfo;
if(argc == 1) {
char myname[256];
gethostname(myname, 255);
host = myname;
}
else
host = argv[1];

hostinfo = gethostbyname(host);
if(!hostinfo) {
fprintf(stderr, "cannot get info for host: %s\n", host);
exit(1);
}

printf("results for host %s:\n", host);
printf("Name: %s\n", hostinfo -> h_name);
printf("Aliases:");
names = hostinfo -> h_aliases;
while(*names) {
printf(" %s", *names);
names++;
}
printf("\n");

if(hostinfo -> h_addrtype != AF_INET) {
fprintf(stderr, "not an IP host!\n");
exit(1);
}

addrs = hostinfo -> h_addr_list;
while(*addrs) {
printf(" %s", inet_ntoa(*(struct in_addr *)*addrs));
addrs++;
}
printf("\n");
exit(0);
}