way of starting a firewall script in debian 9 with kde5 and sddm

[Stephane L]

Hi,I have a firewall script(firewall) that I laucnh with <firewall start>Is 
there a way in debian 9 (with kde5 and sddm) to start this script at the boot 
of the linux system or at the launching of xorg or of kde5 ?
Thanks