Re: Sockets: code works locally but fails over LAN

On 31 Aug 2005 06:03:00 -0700, n00m <n00m@xxxxxxxx> wrote: 
import socket, thread
host, port = '192.168.0.3', 1434
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()

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

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

thread.start_new_thread(VB_SCRIPT,())
thread.start_new_thread(SQL_SERVER,())


This is about the same as:

   mktap portforward --port 1434 --host 192.168.0.3 --dest_port 1433
   twistd -f portforward.tap

You'll find the code behind these two commands here:

<http://cvs.twistedmatrix.com/cvs/trunk/twisted/tap/portforward.py?view=markup&rev=13278>

and here:

<http://cvs.twistedmatrix.com/cvs/trunk/twisted/protocols/portforward.py?view=markup&rev=12914>

And of course, the main Twisted site is <http://twistedmatrix.com/>.

Some differences between portforward.tap and your code include:

portforward.tap will accept multiple connections, rather than just one.  portforward.tap won't print out all the bytes it receives (I assume this is just for debugging purposes anyway - if not, a simple modification will cause it to do this).  portforward.tap won't non-deterministically drop traffic, since Twisted checks the return value of send() and properly re-transmits anything which has not actually been sent.

Hope this helps,

Jp
.