Comment 17 for bug 994575

nm-pptp-service (as seen in the file nm-pptp-service.c) starts pppd with the option

    ipparam nm-pptp-service-%d

where nm-pptp-service's PID is filled in at "%d". The argument of the ipparam option is passed on to ip-up and ip-down scripts as the 6th parameter. So I propose that /etc/ppp/ip-up.d/000resolvconf and /etc/ppp/ip-down.d/000resolvconf no-op in the presence of a sixth argument matching the glob pattern "nm-pptp-service-*".