I'm new to this whole shazam and I'm a little confused. I want to have a server receive data on my computer, and a friend send data on his own computer. The code for my server is as follows:
import socket
HOST = 'HOST'
PORT = PORT
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.bind((HOST, PORT))
s.listen()
conn, addr = s.accept()
with conn:
print('Connected by', addr)
while True:
data = conn.recv(1024)
if not data:
break
conn.sendall(data)
I've blanked out the host ip and the port but I'm not really sure which one I'm supposed to be using for either tbh. The client code goes as follows
import socket
HOST = 'HOST'
PORT = PORT
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.connect((HOST, PORT))
s.sendall(b'Hello, world')
data = s.recv(1024)
print('Received', repr(data))
So my server receives it only when I run the client, not my friend. My question is what IP and ports am i supposed to use? Where can i find these numbers? Why does it only work when I run the client and how can I fix this? And if anybody can direct me to some resources about this topic I don't know what to search up :(
Thanks in advance!
The server should bind to the IP address of whatever interface it expects to receive traffic on. If it might receive traffic on multiple interfaces, you could bind to 0.0.0.0, which means 'all interfaces'. Whatever IP you decide on is what you should set for the server HOST value. For the server port, it could be a specific port or any port (port 0). Just be aware that the client will need to know which port the server is listening on.
The client should connect to the IP address or hostname and port of your server whose address is publicly accessible. This really depends on the network setup.
I suggest having your client connect to the same network as your server and trying again. If it doesn't work, make sure you're server is listening on 0.0.0.0.
If you are on different networks, these networks need to be bridged in some way.
Related
I am trying to set up a python server on AWS.
I would like to access this server through an elastic load balancer. However, I am having some difficulties troubleshooting my issue.
The steps I have taken so far are as follows.
I created a new EC2 instance, ssh-ed into it and created my server and started it.
the code for that server is as follows:
import socket
HOST = '127.0.0.1'
PORT = 3002
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.bind((HOST, PORT))
s.listen()
conn, addr = s.accept()
print("listening")
with conn:
print('Connected by', addr)
while True:
data = conn.recv(1024)
if not data:
break
conn.sendall(data)
Then I created a new target group and registered this ec2 instance to it. The target group is set for the same port as the server (3002).
Next, I created a network load balancer. This load-balancer has a listener set on port 3002 a rule to forward to the target group I have set up.
Finally, I created a local client on my machine with python to communicate with the server.
The code for that client is as follows:
HOST = DNS name for load-balancer
PORT = 3002
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.connect((HOST, PORT))
s.sendall(b'Hello, world')
data = s.recv(1024)
print('Received', repr(data))
My thoughts were the client would connect to the load-balancer on port 3002. The load-balancer, which has a listener on this port, would forward to the target group, which is also using port 3002. Therefore, the ec2 instance would receive the connection on this port and be able to handle it. However, nothing is ever received and the connection times out.
The security groups are configured to allow all TCP traffic on all ports to be allowed (for the time being while I try and figure this out)
Also, this is just me trying to learn how to use a load balancer and connect from a client. I am not planning on using this in a bigger project :) Any help on where my thinking has gone wrong would be greatly appreciated!
Your Python app is only listening to connections from localhost. Change this:
HOST = '127.0.0.1'
To this:
HOST = '0.0.0.0'
I'm trying to make a chat app in Python and I'm having some trouble.
I made a server on which I can connect successfully by using the local IP address. However, when I try to connect to it on an another device with my public IP address, there seems to be a timeout, no errors occur and it's continuously trying to connect.
Edit: I've already set up port-forwarding for my IPv4 address. And the client is using the public IP.
server.py:
import socket
s = socket.socket()
host = socket.gethostbyname(socket.gethostname())
port = 2000
s.bind((host, port))
print("Server started, waiting for incoming connections")
s.listen(5)
connection, address = s.accept()
print("New connection from", address)
while True:
data = connection.recv(1024).decode()
print("received:", data)
ret = data + "+++++++"
connection.send(ret.encode())
client.py
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = #my public ip address from whatsmyip.com
port = 2000
s.connect((host, port))
print("Connected.")
while True:
message = input("msg: ")
s.send(message.encode())
data = s.recv(1024).decode()
print(data)
Well, first of all, is your server in a network with other devices? If you have a router there, the IP you see in whatsmyip.com is the router's, not your computer's, IP. So you'd be trying to connect to it.
You can check that with the command netstat.
I want to create a small TCP server that takes incoming TCP connections from a device that is hooked up via Ethernet to my computer.
The physical port for that has the IP 192.168.1.100 statically assigned to it.
The scripts I use as a client and server are listed at the bottom.
The setup works if I want to send messages between the python scripts. However, I am unable to receive anything from the external device (screenshot from Wireshark capture below). From what I have read I can define an interface to listen to by defining its IP. So I defined the IP of the interface as the host variable. However, I do not receive anything in my script but the messages sent by the other script. I had a similar situation already here on stackoverflow. I thought that defining the correct IP as the host would resolve this issue but it did not.
I am also having a hard time capturing the traffic between the two scripts with Wireshark at all. They did not show up anywhere.
I need to pick up these connections on the eth0 interface with the static IP 192.168.1.100:
tcp_server.py
import socket
# create a socket object
serverSocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# get local machine name
# host = socket.gethostname()
host = "192.168.1.100"
port = 9002
# bind to the port
serverSocket.bind((host, port))
# queue up to 5 requests
serverSocket.listen(5)
while True:
# establish a connection
clientSocket, addr = serverSocket.accept()
print("Got a connection from %s" % str(addr))
msg = 'Thank you for connecting' + "\r\n"
clientSocket.send(msg.encode('ascii'))
clientSocket.close()
and this as a client:
tcp_client.py
import socket
# create a socket object
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# get local machine name
# host = socket.gethostname()
host = "192.168.1.100"
port = 9002
# connection to hostname on the port.
s.connect((host, port))
# Receive no more than 1024 bytes
msg = s.recv(1024)
s.close()
print(msg.decode('ascii'))
I am trying to implement socket programming and want to configure the communication port number for both the server and client to a specific port. I specify the same port number on both the the client and server side but still when the program run's it takes a random port number. How do I fix the port number/make it static?
Server Side Code
import socket
s=socket.socket()
port=12345
s.bind(("192.168.0.111",port))
s.listen(5)
while True:
c, addr = s.accept()
print("got connection from ",addr)
sendingMessage = "Thank you for connecting"
c.send(bytes(sendingMessage, 'UTF-8'))
data = c.recv(16)
receivedData=data.decode("utf-8","ignore")
print (receivedData)
c.close()
if receivedData=="stop":
break
Client Side Code
import socket
port=12345
s=socket.socket()
s.connect(("192.168.43.111",port))
sendingMessage = input("Enter your message : ")
s.send(bytes(sendingMessage, 'UTF-8'))
data = s.recv(32)
receivedData=data.decode("utf-8","ignore")
print (receivedData)
s.close
If you want the client side to also use port 12345, you must also bind the client side port number. The port number given in the s.connect is the remote port to which you're connecting. IOW, your code should look something like this in the client:
s = socket.socket()
s.bind(('', port))
s.connect(("192.168.43.111", port))
You can also specify an IP address in the bind but typically you don't need to as the local IP address will be established by the route to the remote host.
This is the server side program
import socket
s = socket.socket()
host = socket.gethostname()
port = 9077
s.bind((host,port))
s.listen(5)
while True:
c, addr = s.accept()
print("Connection accepted from " + repr(addr[1]))
c.send("Thank you for connecting")
c.close()
This is the client program
import socket
s = socket.socket()
host = socket.gethostname()
port = 9077
s.connect((host, port))
print s.recv(1024)
When i run these two programs on the same computer, it works perfectly.
But when i run the client and server programs in two different computers on the same network, the program doesn't work.
Can anyone please tell me how to send message from one computer to another on the same network.
This is the first time i'm doing any network programming. Any help would be appreciated
Thanks in advance
You are connecting from the client to the client's computer, or well attempting to, because you are using the client's hostname rather than the servers hostname/ip address.
So, to fix this change the line s.connect((host, port)) so that the host points to the servers ip address instead of the client's hostname.
You can find this by looking at your network settings on the server and doing the following:
host = "the ip found from the server's network settings"
host must be edited to the server's ip if the server is not the same computer.