[c-nsp] L2TP tunnel authentication

[Vladimir Litovka]

Colleagues hi

I'm running LNS (Cisco-based) in my network. At the moment, there is 
only class of home subscribers - those ones, who use L2TP tunnel 
immeidately between their CPE and my LNS (avoiding LAC). Configuration 
on LNS is the following:

vpdn enable
!
vpdn-group L2TP
  accept-dialin
   protocol l2tp
   virtual-template 1
*no l2tp tunnel authentication*
!

Now I need to setup classic L2TP scheme: client--LAC--LNS, where client 
will be running PPP to LAC and LAC will create tunnel to LNS. The 
problem is that owner of LAC requires L2TP tunnel authentication. At the 
moment, authentication is switched off (no l2tp tunnel authentication) 
and if I will just turn it on, I will break current subscribers. So, 
questions are:

1) how to configure LNS to authenticate L2TP tunnels only with 
particular endpoints? In my case - with just one LAC.
2) how to configure L2TP authentication locally?
3) how to configure L2TP authentication using Radius?

Many thanks.

-- 
/doka
~~~~~~~~
http://doka-ua.blogspot.com/
http://omar-ha-em.blogspot.com/

"Справа не в церкві і не в наркотиках. Справа у відповідальності та вдячності. Якщо в тебе це є, маєш шанс померти не останньою скотиною." (с) С.Жадан, "Ворошиловград"