avoid dnsmasq to run at boot

Question

I have dnsmasq installed to make my Pi 3 with Raspbian GNU/Linux 8.0 (jessie) into an AP (accesspoint). I want to be able to switch between AP mode and client mode.

This all works fine, but when I boot my pi3 dsnmasq will startup, which I do not want (only for the AP mode).

I removed all links to /etc/init.d/dnsmasq from /etc/rc*.d but it still starts. I set ENEABLED=0 in /etc/default/dnsmasq but it still starts.

I run systemctl disable dnsmasq.service but it still starts.

Only when I add exit 0 to the start of the /etc/init.d/dnsmasq it will not start, but than I can not start it myself.

So a work arround is changing the script removing the exit 0 start it and than adding the exit 0 to the script again. But this seems not the most elegant way of doing this.

is there a way to find out what is starting dnsmasq?

edit:

i have removed the dnsmasq.service from the service dir:

rm /etc/systemd/system/multi-user.target.wants/dnsmasq.service

but still dnsmasq is started:

 ps aux | grep dnsmasq
 /usr/sbin/dnsmasq -x /var/run/dnsmasq/dnsmasq.pid -u dnsmasq -r /var/run/dnsmasq/resolv.conf -7 /etc/dnsmasq.d,.dpkg-dist,.dpkg-old,.dpkg-new --local-service --trust-anchor=.,19036,8,2,49AAC11D7B6F6446702E54A1607371607A1A41855200FD2CE1CDDE32F24E8FB5

to answer the question in the comment:

 systemctl list-units | grep dns
 dnsmasq.service loaded active running   dnsmasq - A lightweight DHCP and caching DNS server

after disable with systemctl:

root@raspberrypi:/home/pi# systemctl disable dnsmasq
Synchronizing state for dnsmasq.service with sysvinit using update-rc.d...
Executing /usr/sbin/update-rc.d dnsmasq defaults
insserv: warning: current start runlevel(s) (empty) of script    `dnsmasq'      overrides LSB defaults (2 3 4 5).
insserv: warning: current stop runlevel(s) (0 1 2 3 4 5 6) of script `dnsmasq' overrides LSB defaults (0 1 6).
insserv: script dnsmasq_run: service dnsmasq already provided!
insserv: script dnsmasq_exit: service dnsmasq already provided!
Executing /usr/sbin/update-rc.d dnsmasq disable
insserv: warning: current start runlevel(s) (empty) of script `dnsmasq' overrides LSB defaults (2 3 4 5).
insserv: warning: current stop runlevel(s) (0 1 2 3 4 5 6) of script `dnsmasq' overrides LSB defaults (0 1 6).
insserv: script dnsmasq_run: service dnsmasq already provided!
insserv: script dnsmasq_exit: service dnsmasq already provided!

there has been a question alike this one (Disabling DHCP Server)

Answer 1

it seems to work now. not 100% what did the trick but i think there were 2 dnsmasq.service files. i removed one and again did the systemctl disable dnsmasq and now it does not start at startup.