Accessing a socket coded using python TCPServer from outside (external machine)

Question

I am making python server using TCPServer. Things that I can do are:
1. use curl from other terminal (curl 10.157.41.14:8444 --data "var1=10&var2=15")
2. use firefox in Xming and type "localhost:8444"

The problem is that when I try to access the server from outside, I can not
I thought this is a problem with the code but I could not find any error with my code.
This is how I configure host and port on my python code:

from SocketServer import TCPServer, StreamRequestHandler
import socket

class MyRequestHandler(StreamRequestHandler):
    def handle(self):
        print "A client tried to connect";
        self.wfile.write("success/n this is a replay from the server");


server = TCPServer((socket.gethostname(), 8444), MyRequestHandler)
host, port = server.socket.getsockname()
address = host + ":" + str(port)
message = "Started string-length server at " + address
print message

server.serve_forever()

I tried changing

server = TCPServer((socket.gethostname(), 8444), MyRequestHandler)

to

server = TCPServer('', 8444), MyRequestHandler);

and to:

server = TCPServer('0.0.0.0', 8444), MyRequestHandler);

None of these works on my case. So what I did next is trying to find if it is a problem in my network configuration or firewall. The problem is that I am not an export on these. Here is what I did:

user@ip-10-157-41-14:/var/www/server$ netstat -tnlpen | grep "8444\|PID"
(Not all processes could be identified, non-owned process info will not be shown, you would have to be root to see it all.)
    Proto Recv-Q Send-Q Local Address           Foreign Address         State       User       Inode       PID/Program name
    tcp        0      0 10.157.41.14:8444       0.0.0.0:*               LISTEN      1014       106226915   31541/python

Then, I did this to find out more about the firewall:

user@ip-10-157-41-14:/var/www/server$ sudo iptables -L
[sudo] password for user:
Chain INPUT (policy ACCEPT)
target     prot opt source               destination

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

another thing I did was opening two terminals (in the same machine)
on terminal-1 I did "nc -l 5000"
on terminal-2 I did "nc 10.157.41.14 5000"
It seems to work. but I do not have access to another Linux machine to try it from another machine.

The problem is that I do not understand the above 2 commands. I spent hours trying to search stackoverflow and other sites for a solution but I did not find a solution that works for me.

In the past(in the same machine), I was able to write cgi python server where I call it using ajax call but I had to write a .htaccess file in the same directory of the python that I was using. The following is my .htaccess file:

Options +ExecCGI
AddHandler cgi-script .py

But the problem I am having now is completely different problem.

Answer 1

My problem turned out to be an Amazon EC2 specific problem.
I am running my server in an instance in Amazon EC2
Amazon instance is located in a Virtual Private Cloud (VPC) with an IP.
You decide if the instance is exposed to the Internet or to remain private.
So, there is an extra level of protection on top of the the EC2 instance.
from the EC2 Dashboard, you can specify open port numbers and close other ones.
It does not matter what I do in the instance level because the configuration in the dashboard is not allowing ports to be open. So, basically I added open ports to the security group in Amazon EC2 and it worked perfectly.