Since version 1.1.08 xl2tpd sends as default SIGKILL to stop the pppd as a workaround for some buggy implementations. (see http://www.xelerance.com/software/xl2tpd/CHANGES ) For unaffected systems this is a problem because after a SIGKILL no ip-down script gets executed. The current stable version of Gentoo seems to be unaffected. I updated the ebuild to change the default behavior of xl2tpd and introduced a new USE-Flag for affected systems.
Created attachment 160553 [details] updated ebuild
Fixed in xl2tpd-1.1.12-r1, but without the new USE flag. If there is a problem in the PPP daemon, I'll deal with it in net-dialup/ppp. Thanks for reporting this issue! Although I use this package, I don't have any specific script that is executed on L2TP session startup/end, so I didn't noticed this problem.