berkeley sockets, running simple client and server connecting - c

Question

I'm just starting out on networking programming in c. I followed a simple tutorial to create a server which accepts a connection and prints out the message sent from the client.
the client takes an argument as the address of the server.
I'm not sure how to specify the address of the server? Is it my machine name?
I'm running the server in one terminal and trying to connect from another. Thanks for any help :)
here's the server code
`#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include<stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
int main(int argc, char *argv[])
{
#define BUFLEN 1500
int fd;
ssize_t i;
ssize_t rcount;
char buf[BUFLEN];
printf("test1");
fd = socket (AF_INET,SOCK_STREAM,0);
if (fd == -1){
printf("Oh dear, something went wrong with read()! %s\n", strerror(errno));
}
struct sockaddr_in addr;
addr.sin_addr.s_addr = INADDR_ANY;
addr.sin_family = AF_INET;
addr.sin_port = htons(500);
if (bind(fd, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
printf("cannot bind socket");
}
if (listen(fd, 20) == -1) {
printf("unable to listen");
}
int connfd;
struct sockaddr_in cliaddr;
socklen_t cliaddrlen = sizeof(cliaddr);
connfd = accept(fd, (struct sockaddr *) &cliaddr, &cliaddrlen);
if (connfd == -1) {
printf("unable to accept");
}
rcount = read(fd, buf, BUFLEN);
if (rcount == -1) {
// Error has occurred
}
for (i = 0; i < rcount; i++) {
printf("%c", buf[i]);
}
}`

Answer 1

printf("test1");
You should add "\n" (newline char) at the end of printed string, so that it prints immediately. Without "\n", printf() buffers its output, and you don't see them.
addr.sin_port = htons(500);
Ports 0 - 1023 are called "well known port" and reserved to the system (root). You should use port 1024 or greater for a test program like this. Changing it from 500 to 1500 (for example) binds successfully.
(You don't see the error message "cannot bind socket" because it has no "\n", as I said above.)
rcount = read(fd, buf, BUFLEN);
You should read from connfd, instead of fd. With these changes, it worked for me.
(I used "telnet localhost 1500" as a client.)