Thanks for the replay, we hope the is on the top of the to do list
By the way, we did some test with our network here to run Mikrotik as LNS, it works with no L2TP tunnel authentication on the LAC,Customer PPP sessions are all works fine until someone reboot they ADSL modem or the ADSL line drops, when those happens the client PPP(L2TP) session stay on the RouterOS forever

, RouterOS software didn’t send keep alive check of something is missing here. So our test result is very much like this guy’s post
http://forum.mikrotik.com/viewtopic.php ... &hilit=lns .
Hopefully the test information will help you guys implement the VPDN function.