I'm trying to code a small web server in python to catch an HTTP post.
But I'm having an issue with the socket.gethostname part of it
here is my sample code
import socket
serversocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
serversocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
serversocket.bind((socket.gethostname(), 8089))
serversocket.listen(1)
while True:
connection, address = serversocket.accept()
buf = connection.recv(164)
print buf
If i change
serversocket.bind((socket.gethostname(), 8089))
to
serversocket.bind(("localhost", 8089))
Everything is fine I can telnet into it, but I need to be able to connect from another web server on the internet so I need to use socket.gethostname but this block my telnet.
You are using a clever trick to get your servers "real" address when potentially several network interfaces are open. serversocket.bind((socket.gethostname(), 8089)) can be broken down to
hostname = socket.gethostname()
dns_resolved_addr = socket.gethostbyname(hostname)
serversocket.bind((dns_resolved_addr, 8089))
You get your local hostname and then ask DNS what it thinks your IP address is, and bind to that. That's the IP address external connections will use so you should use it too.
But it doesn't always work. DNS may not know what your server name is or your server may have a different name in DNS. One example is my home network where I don't have a DNS server and the DHCP addresses handed out by my modem don't appear in a name server anywhere. A similar problem exists if your corporate DHCP doesn't register your hostname with its local DNS.
On my machine, when I go through the steps I get
>>> socket.gethostbyname(socket.gethostname())
'127.0.1.1'
Notice it was 127.0.1.1 ... I think that's some weird Ubuntu thing to keep its routing tables from getting confused. Anyway, one solution is to try to resolve the address and if you don't like it, fall back to a default.
>>> my_ip = socket.gethostbyname(socket.gethostname())
>>> if my_ip.startswith('127.0.'):
... my_ip = '0.0.0.0'
...
>>> my_ip
'0.0.0.0'
Related
I'm trying to get a socket connection between two different terminals. When they are both on the same computer, or on a different computers on the same network (behind my home router), it works fine.
Here is a minimal example of the code I use. On the client side I enter the IP address I get from running ipconfig on the server, it works with both the IPv4 Address and the Temporary IPv6 Address (changing the corresponding flag of course)
SERVER
import socket
ip_address = ""
ipv6 = False # True
PORT = 12345
STREAM = socket.SOCK_STREAM
if ipv6:
FAMILY = socket.AF_INET6
bind_args = (ip_address, PORT, 0, 0)
else:
FAMILY = socket.AF_INET
bind_args = (ip_address, PORT)
server_socket = socket.socket(FAMILY, STREAM)
server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
server_socket.bind(bind_args)
server_socket.listen()
unsecured_sock, client_address = server_socket.accept()
print("accepted from", client_address)
CLIENT
import socket
ip_address = "Entered from ipconfig or whatsmyip.com run from server"
ipv6 = False # True
PORT = 12345
STREAM = socket.SOCK_STREAM
if ipv6:
FAMILY = socket.AF_INET6
bind_args = (ip_address, PORT, 0, 0)
else:
FAMILY = socket.AF_INET
bind_args = (ip_address, PORT)
sock = socket.socket(FAMILY, STREAM)
sock.connect(bind_args)
print("Connected!")
The problems arise when I take one of the computers out of the home network. As I don't have two standard networks I can access at the same time, I test this by connecting one of the computers to the internet via either the 4G on my phone or through a VPN. In either case, I then use the IP I get from whatsmyip.com ran from the server. I've tried all combinations of IPv4 vs IPv6 and whether the server or the client is behind my home router. In all cases it fails (note, I don't get a IPv6 address when the server is accessing the internet via 4G on my phone). In fact, I can't even ping or tracert the ip address of the server from the client terminal.
I suspect that I'm doing something very basic wrong, but I don't know what. I suspected it was to do with port forwarding, so I tried the following UPnP script
import upnpy
upnp = upnpy.UPnP()
devices = upnp.discover()
device = upnp.get_igd()
service = device.WANIPConn1
service.AddPortMapping(
NewRemoteHost='',
NewExternalPort=12345,
NewProtocol='TCP',
NewInternalPort=12345,
NewInternalClient='192.168.0.136', # Local server IP
NewEnabled=1,
NewPortMappingDescription='Test port mapping entry from UPnPy.',
NewLeaseDuration=600)
print("added new port mapping")
which runs correctly but makes no difference. Am I right in thinking that this should be a non issue for IPv6 anyway? If it makes a difference, the provider for my internet says that my connection is IPv6 and that I do not have a proper IPv4 public address. Considering I want this to be portable and, eventually distributed, I'd rather avoid it be dependent on specific settings not accessible to the user.
Any pointers for a networking noob are most appreciated
Clients on the same LAN can connect to the server just fine using the server machine's IPv4 address. However, when I have the clients use my router's external ip and port forward down to the server machine, they cannot connect. Any idea, as to why? I created a server and client in GML using the same port forward and it connected just fine using the external ip, so I am assuming I am missing something needed in Python. Here is the stripped down version of the server code:
# Server variables
host = socket.gethostbyname(socket.gethostname())
port = 65000
max_connections = 100
timeout = 5
# Run Server
socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
socket.bind((host, port))
socket.settimeout(timeout)
socket.listen(max_connections)
run()
I've tried setting the server ip to "" and "0.0.0.0" to no avail. I also tried using the default gateway ip for kicks and giggles. Any advice is appreciated.
I messed up. I thought I had disabled Windows Defender's firewall, but I had only turned off real-time protection. Bah...that's what happens when you're going fast and not paying enough attention. Now it works just fine.
I'm new to Sockets, please excuse my complete lack of understanding.
I have a server script(server.py):
#!/usr/bin/python
import socket #import the socket module
s = socket.socket() #Create a socket object
host = socket.gethostname() #Get the local machine name
port = 12397 # Reserve a port for your service
s.bind((host,port)) #Bind to the port
s.listen(5) #Wait for the client connection
while True:
c,addr = s.accept() #Establish a connection with the client
print "Got connection from", addr
c.send("Thank you for connecting!")
c.close()
and client script (client.py):
#!/usr/bin/python
import socket #import socket module
s = socket.socket() #create a socket object
host = '192.168.1.94' #Host i.p
port = 12397 #Reserve a port for your service
s.connect((host,port))
print s.recv(1024)
s.close
I go to my desktop terminal and start the script by typing:
python server.py
after which, I go to my laptop terminal and start the client script:
python client.py
but I get the following error:
File "client.py", line 9, in
s.connect((host,port))
File "/usr/lib/python2.7/socket.py", line 224, in meth
return getattr(self._sock,name)(*args)
socket.error: [Errno 111] Connection refused
I've tried using different port numbers to no avail. However, I was able to get the host name using the same ip and the gethostname() method in the client script and I can ping the desktop (server).
Instead of
host = socket.gethostname() #Get the local machine name
port = 12397 # Reserve a port for your service
s.bind((host,port)) #Bind to the port
you should try
port = 12397 # Reserve a port for your service
s.bind(('', port)) #Bind to the port
so that the listening socket isn't too restricted. Maybe otherwise the listening only occurs on one interface which, in turn, isn't related with the local network.
One example could be that it only listens to 127.0.0.1, which makes connecting from a different host impossible.
This error means that for whatever reason the client cannot connect to the port on the computer running server script. This can be caused by few things, like lack of routing to the destination, but since you can ping the server, it should not be the case. The other reason might be that you have a firewall somewhere between your client and the server - it could be on server itself or on the client. Given your network addressing, I assume both server and client are on the same LAN, so there shouldn't be any router/firewall involved that could block the traffic. In this case, I'd try the following:
check if you really have that port listening on the server (this should tell you if your code does what you think it should): based on your OS, but on linux you could do something like netstat -ntulp
check from the server, if you're accepting the connections to the server: again based on your OS, but telnet LISTENING_IP LISTENING_PORT should do the job
check if you can access the port of the server from the client, but not using the code: just us the telnet (or appropriate command for your OS) from the client
and then let us know the findings.
Assume s = socket.socket()
The server can be bound by following methods:
Method 1:
host = socket.gethostname()
s.bind((host, port))
Method 2:
host = socket.gethostbyname("localhost") #Note the extra letters "by"
s.bind((host, port))
Method 3:
host = socket.gethostbyname("192.168.1.48")
s.bind((host, port))
If you do not exactly use same method on the client side, you will get the error: socket.error errno 111 connection refused.
So, you have to use on the client side exactly same method to get the host, as you do on the server. For example, in case of client, you will correspondingly use following methods:
Method 1:
host = socket.gethostname()
s.connect((host, port))
Method 2:
host = socket.gethostbyname("localhost") # Get local machine name
s.connect((host, port))
Method 3:
host = socket.gethostbyname("192.168.1.48") # Get local machine name
s.connect((host, port))
Hope that resolves the problem.
host = socket.gethostname() # Get the local machine name
port = 12397 # Reserve a port for your service
s.bind((host,port)) # Bind to the port
I think this error may related to the DNS resolution.
This sentence host = socket.gethostname() get the host name, but if the operating system can not resolve the host name to local address, you would get the error.
Linux operating system can modify the /etc/hosts file, add one line in it. It looks like below( 'hostname' is which socket.gethostname() got).
127.0.0.1 hostname
in your server.py file make : host ='192.168.1.94' instead of host = socket.gethostname()
Pay attention to change the port number. Sometimes, you need just to change the port number. I experienced that when i made changes over changes over syntax and functions.
I was being able to ping my connection but was STILL getting the 'connection refused' error. Turns out I was pinging myself! That's what the problem was.
I was getting the same problem in my code, and after thow days of search i finally found the solution, and the problem is the function socket.gethostbyname(socket.gethostname) doesnt work in linux so instead of that you have to use socket.gethostbyname('put the hostname manually') not socket.gethostbyname('localhost'), use socket.gethostbyname('host') looking with ifconfig.
try this command in terminal:
sudo ufw enable
ufw allow 12397
I have a problem with these client and server codes, I keep getting the [Errno 10061] No connection could be made because the target machine actively refused it
I'm running the server on a virtual machine with Windows XP SP3 and the client on Windows 7 64bit, my python version is 2.7.3. What I want to know is how should I edit the code to use the client and server on different networks! Thanks!
server :
#!/usr/bin/python # This is server.py file
import socket # Import socket module
s = socket.socket() # Create a socket object
host = '0.0.0.0' # Get local machine name
port = 12345 # Reserve a port for your service.
print 'Server started!'
print 'Waiting for clients...'
s.bind((host, port)) # Bind to the port
s.listen(5) # Now wait for client connection.
c, addr = s.accept() # Establish connection with client.
print 'Got connection from', addr
while True:
msg = c.recv(1024)
print addr, ' >> ', msg
msg = raw_input('SERVER >> ')
c.send(msg);
#c.close() # Close the connection
client :
#!/usr/bin/python # This is client.py file
import socket # Import socket module
s = socket.socket() # Create a socket object
host = socket.gethostname() # Get local machine name
port = 12345 # Reserve a port for your service.
print 'Connecting to ', host, port
s.connect((host, port))
while True:
msg = raw_input('CLIENT >> ')
s.send(msg)
msg = s.recv(1024)
print 'SERVER >> ', msg
#s.close # Close the socket when done
PS : code is from internet.
10061 is WSAECONNREFUSED, 'connection refused', which means there was nothing listening at the IP:port you tried to connect to.
There was a firewall product around the year 2000 that issued refusals instead of ignoring incoming connections to blocked ports, but this was quickly recognised as an information leak to attackers and corrected or withdrawn.
Hint: actively refused sounds like somewhat deeper technical trouble, but...
...actually, this response (and also specifically errno:10061) is also given, if one calls the bin/mongo executable and the mongodb service is simply not running on the target machine. This even applies to local machine instances (all happening on localhost).
➪ Always rule out for this trivial possibility first, i.e. simply by using the command line client to access your db.
See here.
So I was facing the same issue,
and the solution that worked for me was...
I am assuming your server and client program are written in python.
First, open one python shell
open and run the Server program first
then open another different python shell
open and run the Client program here
done !!
Using the examples from: https://docs.python.org/3.2/library/socketserver.html
I determined that I needed to set the HOST port to the machine I had the server program running on. So TCPServer on 192.168.0.1 HOST = TCPServer IP 192.168.0.1 then I had to set the TCPClient side to point to the TCPServer IP. So the TCPClient HOST value = 192.168.0.1 - Sorry, that's the best I can describe it.
There is no relationship between error and firewall.
first, run server program,
then run client program in another shell of python
and it will work
instead of localhost of '0.0.0.0', use local network address as host in case of both - the server and the client - code.
host = '192.168.12.12'
port = 12345
use this host address when binding and connecting to the socket.
server.bind((host, port))
client.connect((host, port))
this change solved the issue for me.
The solution is to use the same IP and Port number in both client and server.
Try, in client to use
TCP_IP = 'write the ip number here'
TCP_PORT = writ the port number here
s.connect((TCP_IP, TCP_PORT))
if you have remote server installed on you machine. give server.py host as "localhost" and the port number.
then client side , you have to give local ip- 127.0.0.1 and port number.
then its works
I was facing a similar problem when I was calling REST API using python library and what I found that my server was going into sleep mode which was leading to this. As soon as I logged in to the server via Remote Desktop Connection, my API call used to work.
This could be because of proxy or firewall. If it's proxy, then you need to specify proxy setting at entry point of your code or project.
import os #for proxy
proxy = 'http://10.XX.XX.XX:8X8X' #your own proxy 'http://<user>:<pass>#<proxy>:<port>'
os.environ['http_proxy'] = proxy
os.environ['HTTP_PROXY'] = proxy
os.environ['https_proxy'] = proxy
os.environ['HTTPS_PROXY'] = proxy
#rest of code .....
The below changes fixed my problem.
I struggled with the same error for a week. I would like to share with you all that the solution is simply host = '' in the server and the client host = ip of the server.
The first: Please make sure your port '12345' is opening and then
when you using a different network. You have to use the IP address in LAN. Don't use the 'localhost' or '127.0.0.1'.
The solution here is:
In server
host = '192.168.1.12' #Ip address in LAN network
In client
host = '27.32.123.32' # external IP Address
Hope it works for you
I had errors 10060 and 10061. The reason was in my antivirus(Eset Nod 32). Try to turn off the Firewall of your antivirus as I did or just delete it for a time to test the program. If everything started to work properly, add that program to the exclusion or switch to another antivirus.
Also, try to change the 'host' variable to an empty string:
host = ''
And add socket.AF_INET, socket.SOCK_STREAM to the 's' variable:
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
I was doing this tutorial and they said that windows users will have a problem. They said that you can check the Windows Firewall to fix the problem. Let me show you a quick Google Search on how to change the windows firewall:
Go to Start and open Control Panel. Select System and Security > Windows Defender Firewall. Choose Turn Windows Firewall on or off. Select Turn on Windows Firewall for domain, private, and public network settings.
After that, your app should work. Also, in your client(not server side) the port should be 0.0.0.0 and in the server side, it should be 127.0.0.1.
If the client and server are running on the same machine (as in running 2 programs), it's OK to config both IP address as locahost. However, if you are to run them on different machines (including VMs), you need to
Make sure they are on the same subnet (usually by pinging each other)
The Server needs to config the host IP as its IP address (like 192.168.xxx.xxx instead of localhost or 127.0.0.1). You may find the IP address by running ipconfig on Windows or ip a on Unix-like server
This change worked for me with my Client on Windows and Server on Ubuntu VM.
Some of the other solutions will work if you want to run server.py and client.py on the same machine. I wanted to try and run it on two different machines (windows and raspberry pi), but on the same network.
For me, it was a matter of choosing the correct IP address. If my windows machine is the server, I used the IPV4 address of the windows machine. This can be found by running ipconfig in the command prompt and selecting the 192.168.X.X number. The raspberry client side bounded to the same address. If the raspberry pi is the server, then I would bind to the inet address. You can find this by running ifconfig in the terminal (again the 192.168.X.X).
Note though, the IP addresses are temporary. I believe if you want a more permanent set-up, the server IP address needs to be bound to the router's IP address, then port-forward to the server. That way, the client wouldn't even have to be on the same network.
First you have to start your server( run server.py ) using Command prompt and after that you can easily run client.py because you need a server first which will host so that client.py could be run.
the short term solution is to use the default iis host and port normally 120.0.0.1 and 80 respectively. However am still looking for a more versatile solution.
When you run the code on windows machine, firewall prompts it to allow network access, allow the network access and it will work, if it does not prompts, go to firewall settings > allow an app through firewall and select your python.exe and allow network access.
i already have a post which is quite similiar, but i am getting more and more frustrated because it seems nothing is wrong with my network setup. Other software can be seen from the outside (netcat listen servers etc.) but not my scripts.. How can this be??
Note: It works on LAN but not over the internet.
Server:
import socket
host = ''
port = 80001
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((host,port))
s.listen(1)
print 'Listening..'
conn, addr = s.accept()
print 'is up and running.'
print addr, 'connected.'
s.close()
print 'shut down.'
Client:
import socket
host = '80.xxx.xxx.xxx'
port = 80001
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((host,port))
s.close()
Somebody please help me.
Any help is greatly appreciated.
Jake
Edited again to add:
I think you may be missing some basics on socket communication. In order for sockets to work, you need to ensure that the sockets on both your client and server will meet. With your latest revision, your server is now bound to port 63001, but on the local loopback adapter: 127.0.0.1
Computers have multiple network adapters, at least 2: one is the local loopback, which allows you to make network connections to the same machine in a fast, performant manner (for testing, ipc etc), and a network adapter that lets you connect to an actual network. Many computers may have many more adapters (virtual adapters for vlans, wireless vs wired adapters etc), but they will have at least 2.
So in your server application, you need to instruct it to bind the socket to the proper network adapter.
host = ''
port = 63001
bind(host,port)
What this does in python is binds the socket to the loopback adapter (or 127.0.0.1/localhost).
In your client application you have:
host = '80.xxx.xxx.xxx'
port = 63001
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((host,port))
Now what your client attempts to do is to connect to a socket to port 63001 on 80.xxx.xxx.xxx (which is your wireless internet adapter).
Since your server is listening on your loopback adapter, and your client is trying to connect on your wireless adapter, it's failing, because the two ends don't meet.
So you have two solutions here:
Change the client to connect to localhost by host = 127.0.0.1
Change the server to bind to your internet adapter by changing host = 80.xxx.xxx.xxx
Now the first solution, using localhost, will only work when your server and client are on the same machine. Localhost always points back to itself (hence loopback), no matter what machine you try. So if/when you decide to take your client/server to the internet, you will have to bind to a network adapter that is on the internet.
Edited to add:**
Okay with your latest revision it still won't work because 65535 is the largest post available.
Answer below was to the original revision of the question.
In your code posted, you're listening (bound) on port 63001, but your client application is trying to connect to port 80. Thats why your client can't talk to your server. Your client needs to connect using port 63001 not port 80.
Also, unless you're running an HTTP server (or your python server will handle HTTP requests), you really shouldn't bind to port 80.
In your client code change:
import socket
host = '80.xxx.xxx.xxx'
port = 63001
And in your Server Code:
import socket
host = ''
port = 63001
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((socket.gethostbyname(socket.gethostname()), port ))
In your server script you have port = 80, but you don't ever use it. It looks like the server is listening on 63001. And the client is connecting to 80.
If you're going to use 80, make sure you don't have an http server trying to use the port at the same time as well.