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VPN via VPN with VNC

VPN via VPN with VNC

VPN via VPN with VNC

(OP)
I have a strange issue.  In my office I have a PC used for remote connections to our clients.  It runs various dial up programs and the Cicso VPN client. From outside the office, I can VPN into the office, start a VNC session to the PC and then start a Cisco VPN session from that PC to a customer. Four out of the five entries in my client work fine.  The fifth entry starts to connect and then I lose my VNC session to the PC. I'm assuming the networking has changed once this entry connects, but why do the others work? What can I do to make the fifth function like the other four?

RE: VPN via VPN with VNC

Why not use logmein or teamviewer?

RE: VPN via VPN with VNC

(OP)
Tried logmein.  Same problem - I get disconnected from the office PC as soon as that Cisco VPN session is established.

RE: VPN via VPN with VNC

obviously the routing is different. At the limitied info you have given I am going to guess this...

On the four out of the PC's that your work once you VPN you are effectly on the local LAN. You then VNC to another LAN address. From this PC another VPN is etablished. At this point routing tables are ammended for the new VPN but the reason you don't be disconeccted is because YOUR VNC connection is from a local IP to local IP so any ammendments to the PC (you VNC to) of it's routing table will not affect local connections.

This is different with the 5th PC. When you VPN you will get an IP, lets say 192.168.1.54 but the PC you then VNC to is on a different subnet of say 192.168.2.87. You can still connect fine because there is router somewhere between the VPN SERVER (not your PC) that you have tunneled into and the VNC machine that takes care of routing. When packets come back from the VNC machine they have to be routed. This is key to the next part. Now when you try to establish a new VPN from this VNC machine the same happens as stated above. It ammends routing tables on theis PC to take into account the VPN. At this point IT WILL drop your connection because to send packets back to you they need to be routed...This will now go across the VPN and never reach you. In the first scenario it doesn't apply because they are on the local subnet and don't need to be routed.

If this is not the case it will 100% be on the right track. Some extra routing is going on with the 5th PC that doesn't happen with the other 4. Once this kicks in it breaks the path back to your PC.

Take a look at my IT blog guides, knowledgebase  and technical resources at http://think-like-a-computer.com

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