Python Script to dial a VPN connection, automate VPN routing table updates.

[Mark Hammond]

Warren Postma wrote:

> Sorry for the nearly-off-topic nature of this post, but ....
> 
> I work from home now, and there's something in Windows 2000 that's
> annoyingly manual:
> 
> I have a permanent internet connection via @home cable modem, and I "dial"
> through that to create a VPN connection to the office.  The problems are
> two:
> 
> (1) Windows won't accept or save my userid, password and the domain name, so
> I have to enter it manually.
> 
> (2) After connecting, I have two default gateways in my routing tables
> (ROUTE PRINT) and I need to update it so only the traffic that is destined
> to the office goes through that interface.  The IP addresses I get given are
> different each time, making a batch file insufficient, so voila, a perfect
> use for python.

I have very similar problems.  Here is a script I wrote for the purpose. 
  It doesnt handle authentication sa Windows does remember the password 
etc for me.

When run with a command-line option being the VPN connection name, it 
establishes a connection to the named site.

Once connected, or if an argument is not given it attempts to find the 
IP of the VPN connection and manually add a route for the VPN.

Thus, I generally use it with no options after manually connecting - not 
for any good reason actually, just that is the way I do it :)

import os
import sys
import win32ras

def Connect(rasEntryName, numRetries = 5):
     # See if already connected
     for info in win32ras.EnumConnections():
         if info[1] == rasEntryName:
             print "Already connected to '%s'" % (rasEntryName,)
             return 1
     dial, have_pw = win32ras.GetEntryDialParams(None, rasEntryName)
     if not have_pw:
         print "Error: The password is not saved for this connection"
         print "Please connect manually selecting the 'save password' 
option and try again"
         sys.exit(1)
     retryCount = numRetries
     bValid = 0
     print "Connecting to:", rasEntryName
     while retryCount > 0:
         rasHandle, errCode = win32ras.Dial(None, None, dial, None)
         if win32ras.IsHandleValid(rasHandle):
             bValid = 1
             break
         print "Retrying..."
         win32api.Sleep(5000)
         retryCount = retryCount - 1
     return bValid

def FixRoute():
     data = os.popen("ipconfig", "r").readlines()
     have_ppp = 0
     ip_str = None
     for line in data:
         if line.startswith("PPP"):
             have_ppp = 1
         if have_ppp and line.strip().startswith("IP Address"):
             ip_str = line.split(":")[1].strip()

     if ip_str is None:
         print "ERROR: could not find the PPP ip address"
     else:
         print "Your PPP IP address is", ip_str
         cmd = "route add 192.168.2.0 mask 255.255.255.0 %s" % (ip_str,)
         print cmd
         os.system(cmd)
         print "Route updated."

if len(sys.argv) == 2:
     if not Connect(sys.argv[1]):
         print "Could not connect to '%s'" % (sys.argv[1],)
         sys.exit(1)
else:
     print "No connection name specified - just adding route..."
FixRoute()