Why am I getting the error connection refused in Python Sockets

Question

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

try this command in terminal   sudo ufw enable ufw allow 12397

User · Answer

in your server py file make   host   192 168 1 94  instead of host   socket gethostname

User · Answer

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

User · Answer

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

[python] Why am I getting the error "connection refused" in Python? (Sockets)

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