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[Openvpn-users] Windows clients respond to Netbios name queries with the wrong address


  • Subject: [Openvpn-users] Windows clients respond to Netbios name queries with the wrong address
  • From: "Andrew Hamilton" <ahamilton@xxxxxxxxxxxxxx>
  • Date: Tue, 16 Oct 2007 12:09:46 +0900

Hello all,
 
I realize that this is not a OpenVPN-specific problem (the same problem occurs when using PPTP), but I was hoping that someone on the list will have come across this before and fixed it.
 
A very common brand of multi-function printer in Japan has the ability to scan to a PDF file and deliver it into an SMB share.  As soon as we connected our client's fileserver to the OpenVPN network we are building for remote support, the scanner stopped being able to see the SMB shares on that fileserver.
 
I had a quick look with a packet sniffer and noticed the following (I suspect incorrect) behaviour when the OpenVPN (tap interface) is connected:
 
Scanner-> Server:  NB Name Query
Server (TAP Interface) -> Scanner:  192.168.16.8  <-- This is the correct answer; that is, the IP address of the ethernet interface, but the answer was sent out the TAP interface, so the scanner never got it.
 
Then later:
 
Scanner -> Broadcast:  NB Name Query
Server (Ethernet Interface) -> Scanner:  10.85.1.1 <-- This is the IP address of the TAP interface..  The scanner got it, since it was sent on the Ethernet interface, but it was the wrong address.
 
Even if I go into the TAP interface properties and uncheck the bindings for "client for Microsoft networks" and the like, only leaving TCP/IP checked, I still see the same behaviour.
 
Has anyone else seen this happen?  Can I fix this in any way besides setting up a proper DNS infrastructure at the client site?
 
Thanks,
 
Drew Hamilton
Emissary Computer Solutions, Tokyo