Due to a bug in the openl2tp.so pppd plugin the slave pppd processes gets killed and torn down every two minutes.
Created attachment 311003 [details, diff]
Patch to fix the issue.
I've also reported upstream to samba/ppp, however, I have no idea how to dig those reports back out of the ticket system they've got, thus I just linked to the same issue I posted to openl2tp.org.
is this still valid with 2.4.7?
I have not tested, but a quick glance at the code shows that it's still valid, and I still "autopatch" all my ppp installs with this exact patch, and they are working correctly. No new releases op openl2tpd has been released that I'm aware of so there were no changes on that side that would negate the need for this.