Hi Alexander,
Thank for replying me!
I tried follow your ideas.
My if-down script was not working.
However i find out this issue regrading xl2tpd.
In/Makefile/ of xl2tpd source code v 1.3.6 :
"/-DTRUST_PPPD_TO_DIE //
// ...//
// # The cost of not trusting pppd to die (and shoot it down
hard), is that your//
// # pppd's //*ip-down scripts*//will not have a chance to run/."
So i just enable /-DTRUST_PPPD_TO_DIE /and rebuild xl2tpd.
The problem solved. My if-down script 's working well now!
Greetings !
Nam.