I have setup a LAN to LAN PPTP vpn between a draytek vigor 2920 and a vigor 2820.

The VPN works fine however i would like this to be a dial-on-demand VPN hence i have not checked "Always On" or "Ping to keep alive" and have set the idle timeout to 150.

The VPN however does not timeout, when looking at the connection manager the Tx counter goes up by about 12 every 10 seconds and the Rx goes up by about 5 every 10 seconds.
I have disabled multicasting and NetBIOS naming over the vpn however this has made no difference, is there something i have missed?

Thanks in advance.

Well i fixed the problem with the timeout, it was because Netbios naming packet was set to pass. However the VPN does not behave like a dial-on-demand VPN. Do the drayteks support this?