[vpn-help] Bug report: same subnet both ends of the tunnel doesn't work.

[Matthew Grooms]

On 7/28/2010 9:29 AM, Ian Fraser wrote:
> Hi, I have a problem with the Shrew Soft Windows VPN client and would
> like to submit the following bug report:
>
> Problem: Recently changed from Junipers VPN client to Shrew Soft's
> VPN client for windows. I happily completed all testing without a
> problem. After the users switched some of them complained of various
> behaviour such as: Connects RDP client for a short while(10-20 mins)
> then disconnects and refuses to reconnect. Tunnel comes up, until try
> they to connect the RDP client, then the tunnel drops. Tunnel comes
> up, but RDP client fails to connect.
>
> After some time, it emerged that the users experiencing these
> problems were using home connections that used the same subnet range
> as our internal network (192.168.1.0/24 for example). I am hoping
> that because other VPN client software can cope with this situation,
> this is not an insurmountable problem.
>
> VPN Client Version : 2.1.5-release (have also tried 2.1.6-rc-1)
> Windows OS : Windows Vista and XP Gateway Make/Model: Juniper SSG-140
> Gateway OS version: 5.4
>

Hi Ian,

I can only think of one way to cope with this situation and that's to 
cut off access to the local network by promoting the identical route 
that points the distant network. The Shrew Soft client is designed to 
increment the route metric on existing routes and use the lowest route 
metric possible to reach distant networks. I'll try to re-create the 
scenario you describe and see if I can re-produce, and with any luck, 
correct the issue.

-Matthew