#include <stdio.h>
#include <netdb.h>
#include <netinet/in.h>

#define _SERV "127.0.0.1"
#define _PORT 80

void main(int argc, char *argv[])
{
        int port,s;
       
        struct  sockaddr_in     serv_addr;
        struct  hostent         *server;

        port = _PORT;
        server = gethostbyname(_SERV);
        if (!server)
        {
            fprintf(stderr, "Can't resolve \"%s\"\n", _SERV);
            exit(1);
        }
        s = socket(AF_INET, SOCK_STREAM, 0);
        bzero(&serv_addr, sizeof(serv_addr));
        serv_addr.sin_family = AF_INET;
        bcopy(server->h_addr, &serv_addr.sin_addr.s_addr,
        server->h_length);
        serv_addr.sin_port = htons(port);

        if (connect(s, &serv_addr, sizeof(serv_addr)) < 0) 
        {
           perror("Unable to connect to remote host");
           exit(1);
        }
}
Connexion sur le port 80.Ici, on place l’ip et le port dans le source pour éviter d’ alourdir les arguments.