Node.js在Heroku/AppFog上的TCP服务器

这是我在Heroku和AppFog上托管的node.js TCP服务器的代码。我的客户端是用C编写的，它只是向服务器发送消息并获得响应。当我在本地托管服务器时，它们工作正常。但是当我尝试连接到在线服务器时，客户端失败("连接错误:操作超时")。知道发生了什么吗?

var net = require('net');
var server = net.createServer(function (socket) {
    socket.on("data", function(data){
    socket.write(data.toString());
  });
});
var port = process.env.VCAP_APP_PORT || 8081;
console.log(port);
server.listen(port);

Client(C) from http://www.linuxhowtos.org/C_C++/socket.htm):

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h> 
void error(const char *msg)
{
    perror(msg);
    exit(0);
}
int main(int argc, char *argv[])
{
    int sockfd, portno, n;
    struct sockaddr_in serv_addr;
    struct hostent *server;
    char buffer[256];
    if (argc < 3) {
       fprintf(stderr,"usage %s hostname portn", argv[0]);
       exit(0);
    }
    portno = atoi(argv[2]);
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0) 
        error("ERROR opening socket");
    server = gethostbyname(argv[1]);
    if (server == NULL) {
        fprintf(stderr,"ERROR, no such hostn");
        exit(0);
    }
    bzero((char *) &serv_addr, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    bcopy((char *)server->h_addr, 
         (char *)&serv_addr.sin_addr.s_addr,
         server->h_length);
    serv_addr.sin_port = htons(portno);
    if (connect(sockfd,(struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0) 
        error("ERROR connecting");
    while (1){
    printf("Please enter the message: ");
    bzero(buffer,256);
    fgets(buffer,255,stdin);
    n = write(sockfd,buffer,strlen(buffer));
    if (n < 0) 
         error("ERROR writing to socket");
    bzero(buffer,256);
    n = read(sockfd,buffer,255);
    if (n < 0) 
         error("ERROR reading from socket");
    printf("%sn",buffer);
    }
    close(sockfd);
    return 0;
}