Hi!
Im using PPTP VPNs for trivial tasks.
As I know on VPN we have one client and one Server.
The client has one option to up the VPN tunnel when it detects traffic that should go throught the tunnel (Dial on Demand option).
But what about if a computer on the router set as VPN Server wants to transfer something and the VPN it’s down ?
How I could have the Dial on Demand option in both sides of the VPN tunnel ?
Regards,
why would you like to use dial on demand ? just let the connection alive and leave it that way…if no traffic is generated by computer no traffic goes through the VPN except the information packet between client and server, but that traffic is not much
u want to make the Server call the client to connect…
usually the server is waiting for a call from the client!!!
if there is no a third party involved in your schema there is no way that a client will know that the server is looking for him.
Now for fun
am… lets assume that your girlfriend has no GSM (third party) but have your number to connect you (your home phone number being the user/pass). If she is somewhere around the market she could use the street phone device (being a hotspot to get internet connected) and dial you because she want something. Its OK she can call u because u don’t move → u stay at home (home being the DATACENTER) and don’t move, but wait!
How can u call her back… you can’t its a street number from somewhere where she is not now 
But lets say u use third party being the GSM number of her friend that is with her and u know the number, so you call and say, please tell my girl to call me, I have info for her
Something’s wrong with me today why do I write so much
Oh. Maybe you are missing your girlfriend as she has forgotten her mobile so you cannot call her…?