CODEWITHSUNDEEP
pythonlinuxsockets
sans0909
sans0909

Reputation: 435

Errno 111: Connection refused only in python IDLE

When I try to execute Python server socket program and client socket program (both running in same linux machine) in Linux terminal I don't get any error, server accepts connection and sends data to client successfully.

But when I execute the same programs in python IDLE I get "[Errno 111] Connection refused" error.

What is the difference in both execution?

I'm using serversock.bind(('',port#)) in server and in client i'm using clientsock.connect(('localhost',port#))

Server.py

import socket

serversock = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
host = ''
print host
port = 5800
serversock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
serversock.bind((host,port))
serversock.listen(2)

try:
    while True:
        csock,addr = serversock.accept()
        print 'Recieved address from %s '% str(addr)
        csock.send('hello')
        csock.close()

except Exception,e:
    print e

client.py

import socket

 try:
   c = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
   host = 'localhost'
   port = 5800
   c.connect((host,port))
   data = c.recv(1024)
   print data

except Exception,e:
   print e

finally:
   c.close()

Upvotes: 1

Views: 1080

Answers (1)

Serge Ballesta
Serge Ballesta

Reputation: 148890

Server side you must use:

serversock.bind(('',port#))    # binds to port
serversock.listen(5)           # actually listen to port and allow 5 incoming calls
conv = serversock.accept()     # accept first incoming call

The connection will only be accepted after the listen call, before it, you have only bound a socket, but have not declared that you were ready to accept incoming calls, so they are refused.

With added code, another possible error cause is that you close connection (server side) immediately after sending data. That is bad: the close condition can destroy the socket before the data has actually been sent.

You should use a graceful shutdown:

  • server side:

    csock.send('hello')
csock.shutdown(socket.SHUT_WR) # shutdown the socket
csock.read() # wait the close from peer
csock.close()

  • client side: you can leave the code as is in your use case you do not send anything to server, so when the client has finished reading it can safely close the socket

Anyway you should close serversock when everything is finished

try:
    ...
except ...:
    ...
finally:
    serversock.close()

Upvotes: 1

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