Python 3 - Hosting a server - python

Basically, I'm making a Game Server for my Python text-based game. What I want is to let each player make his own local server and/or public server but I don't seem to get it. I've tried this:
serversocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = input("Enter an IP: ")
port = 10922
serversocket.bind((host, port))
But whenever I'm running it and type my own external IP, it throws me this error:
"OSError: [WinError 10049] The requested address is not valid in its context"
Edit: To add to this, it only works with host = "127.0.0.1" but the server isn't public that way.
Can anyone help with this?

The reason it throws this error is because you are binding to an unknown address hence the error.
To bind the socket to your IP, do: socket.gethostbyname(socket.gethostname()) in the place of the address.
socket.gethostname() gets the hostname of the computer e.g. DANS_PC
socket.gethostbyname() looks up the IP of the hostname that is given in the parameters.
To make the server public however, do the same but port forward your computers IP address in your router settings.

Related

Create TCP Server accessible on remote networks

A project I am working on has an Android app as a front-end and a Python program that would be used as the back-end.
I want to send data from the Android app (primarily images) to the Python program, do some processing and send the result back to the Android app.
I have found numerous tutorials that suggest using the socket module in python to create the server side, but all tutorials show the server on local network only (For testing purposes I created the client side also in Python, but it would be converted to Java later on)
The server code:
from requests import get
import socket
public_ip = get('https://api.ipify.org').text
print('My public IP address is: {}'.format(public_ip))
# getting the hostname by socket.gethostname() method
hostname = socket.gethostname()
# getting the IP address using socket.gethostbyname() method
local_ip = socket.gethostbyname(hostname)
# printing the hostname and ip_address
print(f"Hostname: {hostname}")
print(f"IP Address: {local_ip}")
#
HOST = local_ip
PORT = 80 # Port to listen on (non-privileged ports are > 1023)
with socket.socket(family=socket.AF_INET, type=socket.SOCK_STREAM, proto=0) as s:
s.bind((HOST, PORT))
s.listen()
conn, addr = s.accept()
with conn:
print('Connected by', addr)
while True:
data = conn.recv(1024).decode('utf-8')
if not data:
break
conn.sendall(data.encode('utf-8'))
The client code:
import socket
HOST = '…' # I modify it to the server's public IP address, as printed from the server code
PORT = 80 # The port used by the server
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
with socket.create_connection((HOST, PORT)) as s:
s.sendall(b'Hello, world')
data = s.recv(1024)
print('Received', repr(data))
Using the code above, if I try using any port other than 80 I get ConnectionRefusedError: [Errno 111] Connection refused. And for port 80, I get TimeoutError: [Errno 110] Connection timed out.
In both cases, I try to connect from a device on another network.
I tried to use the ping command in Windows CMD to check the connection to the server, and I get 'connection refused message'.
I understand that the Firewall is what probably blocks the connection, but I don't know how to bypass it. I added a new rule in the Inbound Rules section (as suggested on other websites) but for no avail… The results were the same.
How can I make the connection between remote devices on different networks?
Thanks in advance ☺
In order to connect to your server using a TCP socket connection, you need to make sure your server can listen on a port on a publically available IP address.
If the External IP address is assigned to your computer directly,
and if you run the server code on that computer, then the TCP port opened by the server code should be available on the internet.
However, IP addresses are often assigned to a modem/router in home networks,
instead of assigning them to any connected device directly.
To find out if your External IP address is assigned to the computer directly you can use tools that your OS support (eg. ipconfig on windows). If you can see the IP address returned by api.ipify.org, then it means your computer is connected directly. You can change your code to connect using publically exposed IP:
HOST = public_ip
If this is successful means your computer is assigned an external address directly. Which is highly unlikely.
There are several workarounds for this problem though:
1) Configure your router to forward port
Configure your router to forward all connections to it's external TCP port, to an internal host in your network which is assigned to your computer. Please find instructions how it is done for your router.
2) Setup a remote proxy
If you don't have permission to change your router settings you can set up a remote proxy listening on the TCP port. While there is a number of ways of doing this, very popular is to set up a remote SSH tunnel, for that you need to have a server with SSH access and an external IP. Run this command:
ssh -R 80:localhost:8080 root#your-ssh-server-host
You can also use a third-party service that exposes your private host on the internet like:
Ngrok (Commercial, with free plans)
Localtunnel (Open Source, can be self-hosted)

TCP Socket not connecting [WinError 10060] - Python

I'm making a chat app using sockets in python, but when I try to connect from a different computer then it says:
C:\Users\James\OneDrive\Documents\Python\Projects\Gui Chat\client.pyw
[WinError 10060] A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond
This is the server code for the socket:
host = socket.gethostbyname(hostname)
port = 55555
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind((host, port))
print(f"IP: {server.getsockname()[0]}\nPORT: {server.getsockname()[1]}")
server.listen()
I also have a while True loop accepting all requests:
while True:
client, address = server.accept()
print(f"Connected with {str(address)}")
On the client end this is the socket code:
IP = simpledialog.askstring("IP", "Enter IP address", parent=root) # "192.168.1.252" # input("Enter IP: ")
nickname = simpledialog.askstring("Nickname", "Choose a nickname", parent=root)
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
client.connect((IP, 55555))
except Exception as e:
print(e)
The programme asks for the IP address each time, and when I put in the correct IP for the server computer, it comes up with the error above. It works if I try to connect from the same computer, and they are both on the same network. It was working recently, and now it has just stopped working.
UPDATE:
I have set the server ip to 0.0.0.0, I have set up a port forwarding rule, I have checked the firewall and allowed incoming and outgoing connections, and I have run nmap with these results:
Code issues
First try binding server on localhost or 127.0.0.1.
FireWall/Ports issues
Check if your computer's default computer/antivurus
firewall (where server is hosted) allow connections
on your port 55555.
And if computer with client is outside your home network
point to router public IP address and make sure you have
port forwarding setup on router.
Address issues
Are you sure that IP you are writing in client is correct.
Go to your computer with server and check that IP.
Windows:
Go to cmd or Power Shell and type ipconfig, then find
section IPv4 Address and look that address you habe there.
Linux / MacOS
Go to your terminal and type ifconfig -a, and
it should be somewhere there, but I don't have those systems,
so I can't test it for you. If it does't work try to search how to
find that out.

Python: Connect using sockets via external IP

Today, I have made my very first sockets program - I made a client and a server that message each other (kind of like a chat) using sockets. When using the internal IP as 'host', The connection is established, otherwise using the external IP, no connection is established.
Edit 1:
#Client
s = socket.socket()
host = '123.123.123.123'
port = 9999
s.connect((host, port))
#Server
host = ''
port = 9999
s = socket.socket()
s.bind((host, port))
s.listen(5)
connection, address = s.accept()
How will this work properly with, for example, a laptop? Since your IP changes each time you switch Wifi, how would I be able to create a program that would permanently work with this specific laptop?
I understand that I have to port-forward the specific port to a specific internal machine such as 192.168.0.5. but what if I'm using a laptop and I don't have access to the WIFI router. I wouldn't have access to every router a laptop uses.
I want the code to be permanently compatible.
Use DynDNS.com or NoIP.com portal. You install program on laptop which check your IP frequencly and sends current IP to portal which assigns this IP to your address like "my_laptop.noip.com". Then people can access your laptop using "my_laptop.noip.com" instead of IP address.
You always assign socket to IP of local network card (NIC) like WiFi. You can't assing to external IP. You have to config your router so requests to external IP:port will be send to your local IP:port. Of course Internet Provider routers can block your ports and it will not work.

Python 2.7 Socket connection on 2 different networks?

Title says all. I have a client and a server setup, but they only work with localhost. How can I connect to the socket from a different network?
Client
# Echo client program
import socket
print "Client"
HOST = "localhost" # Symbolic name meaning all available interfaces
PORT = 5001
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST,PORT))
while True:
data2 = raw_input()
s.sendall(data2)
Server
# Echo server program
import socket
print "Server"
HOST = "" # Symbolic name meaning all available interfaces
PORT = 5001 # Arbitrary non-privileged port
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((HOST, PORT))
s.listen(1)
conn, addr = s.accept()
print 'Connected by', addr
while 1:
data = conn.recv(1024)
print data
if data == "Ping":
print "Pong!"
conn.close()
Check your public ip address using online tools like http://whatismyipaddress.com/
Check your local ip address using ipconfig -a in windows ifconfig in linux.
Now if you are behind a dsl router (generally, you are) these addresses are completely different. So you have to tell your router to send whenever a connection attemp received to a TCP port XXXX , forward it to "My Machine" (called Port Forwarding ). Although port forwarding settings are similar in most routers, there is no standard (Generally under NAT / Port Forwarding menu items on your router web configuration interface ). You may have to search instructions for your specific model.It's a good idea to set your computer to use a static ip address before port forwarding.Otherwise, the settings will be invalid if your computer is assigned another IP adress via DHCP.
If port forwarding is successful, now you only have to set your client application to connect to your public ip address. In your specific situation it's HOST = "X.X.X.X" in your client source code. Check if port forwarding works with a socket tester application you downloaded from somewhere. ( Don't test it with your experimental code, use an application you are sure that it's working). All did not work, check out the note below. It's the last resort ,though.
Note : Some ISP's put their clients behind an extra firewall for security. A simple method to detect if this is the situation is , your Wan ip address you see in your router web interface will be different from what you see in online tools like whatsmyip. In this situation no matter what you do , you will not be able to connect. You have to call your ISP and tell them to disable firewall for your connection . You may have some difficulties to explain them what you are talking about :).

Python server only working on local wifi

The code:
import socket, threading
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind(("my ipv4 from ipconfig", 12))
server.listen(5)
def client_handler(client_socket):
request = client_socket.recv(100)
print "[*] Received: " + request
client_socket.close()
while True:
client, addr = server.accept()
print "[*] Accepted connection from: %s:%d" % (addr[0], addr[1])
servert = threading.Thread(target=client_handler, args=(client,))
servert.start()
So the server seems to work fine locally but if i ask my friend on a different network to connect, it doesn't connect. I tried port forwarding from the router
http://i.stack.imgur.com/wSUir.png ( cant post img apparently cause my_reputation < 10)
I also tried using the ip i get from the whatismyip website, but i get the error:
error: [Errno 10049] The requested address is not valid in its context
Any ideas on what i could do so other people can connect? Thanks.
When you're trying to access your server from outside your LAN, you ought to use 0.0.0.0 as your IP address while creating your socket object. 0.0.0.0 usually means the default route (the route to "the rest of" the internet, aside from routes in your local network etc.). If you use the IP address allotted by DCHP (in your case, the router), the devices connected to the network (router) is only aware of the fact that your IP address is what you get in $ifconfig command, a private IP address which the client is unaware

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