Re: Sockets: code works locally but fails over LAN

n00m wrote:
> import socket, thread
> host, port = '192.168.0.3', 1434

Consider using INADDR_ANY instead of the specific host IP
address. The empty string will resolve to INADDR_ANY if passed
as the host to bind(). (Though that's not the problem.)

> s1 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
> s2 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
> s2.connect((host, 1433))
> s1.bind((host, port))
> s1.listen(1)
> cn, addr = s1.accept()

You probably want the the accept() in a loop.

> def VB_SCRIPT():
> while 1:
> data = cn.recv(4096)
> if not data: return
> s2.send(data)

Use sendall(), not send().

> print 'VB_SCRIPT:' + data + '\n\n'
>
> def SQL_SERVER():
> while 1:
> data = s2.recv(4096)
> if not data: return
> cn.send(data)

As above, use sendall().

> print 'SQL_SERVER:' + data + '\n\n'
>
> thread.start_new_thread(VB_SCRIPT,())
> thread.start_new_thread(SQL_SERVER,())
>
> =============================================
>
> The above code acts as an intermediator between a very simple VB script
> and SQL Server. Like follows:
> the vbs sends its requests to "fake" port 1434 and the python code
> catches and re-sends them to sql server which listens to its DEFAULT
> port = 1433... And vice versa.
[...]
> It works fine (I see all client/server data printed in IDLE window)but
> only locally. I.e. if vbs, python and sql server run on the same
> machine.
[...]

My first two guess are:

     The client is trying to make more than one connection.
     Putting accept in a loop and moving some stuff will support
     that.

     The send() call is not sending all the data. Using sendall()
     should fix that.

Try the following, but *not in Idle*. The code doesn't yet have
a clean stopping method, and the run-on threads will screw-up
Idle.

import socket, thread

sqls_host, sqls_port = '192.168.0.3', 1443
proxy_host, proxy_port = '', 1434

# How I tested it:
# sqls_host, sqls_port = 'www.google.com', 80

def VB_SCRIPT():
     while 1:
         data = cn.recv(4096)
         if not data: return
         s2.sendall(data)
         print 'VB_SCRIPT:' + data + '\n\n'

def SQL_SERVER():
     while 1:
         data = s2.recv(4096)
         if not data: return
         cn.sendall(data)
         print 'SQL_SERVER:' + data + '\n\n'

s1 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s1.bind((proxy_host, proxy_port))
s1.listen(5)

while 1:
     cn, addr = s1.accept()
     s2 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
     s2.connect((sqls_host, sqls_port))
     thread.start_new_thread(VB_SCRIPT,())
     thread.start_new_thread(SQL_SERVER,())

-- 
--Bryan