¿Por qué ifup no ejecuta todos los scripts if-pre-up.d?

$ ll /etc/network/if-pre-up.d/

total 20
drwxr-xr-x 2 root root 4096 Jan 15 16:43 ./
drwxr-xr-x 7 root root 4096 Jan 14 21:29 ../
-rwxr-xr-x 1 root root  344 Apr 28  2012 ethtool*
-rwxr-xr-x 1 root root  158 Jan 14 22:01 iptablesload.sh*
-rwxr-xr-x 1 root root 3839 May  3  2012 wireless-tools*
lrwxrwxrwx 1 root root   32 Dec  4 13:00 wpasupplicant -> ../../wpa_supplicant/ifupdown.sh*

$ sudo ifup --all -v

run-parts --verbose /etc/network/if-pre-up.d
run-parts: executing /etc/network/if-pre-up.d/ethtool
run-parts: executing /etc/network/if-pre-up.d/wireless-tools
run-parts: executing /etc/network/if-pre-up.d/wpasupplicant
run-parts --verbose /etc/network/if-up.d
run-parts: executing /etc/network/if-up.d/000resolvconf
run-parts: executing /etc/network/if-up.d/avahi-autoipd
run-parts: executing /etc/network/if-up.d/avahi-daemon
run-parts: executing /etc/network/if-up.d/ethtool
run-parts: executing /etc/network/if-up.d/ntpdate
run-parts: executing /etc/network/if-up.d/openssh-server
run-parts: executing /etc/network/if-up.d/upstart
run-parts: executing /etc/network/if-up.d/wpasupplicant

¿Por qué no se ejecuta iptablesload.sh? ¿Hay alguna otra ubicación donde se establezca una lista de scripts previos?

Tuve el mismo problema. Por lo que puedo decir, si elimina el ".sh" final, esto debería funcionar como se esperaba.

sudo mv /etc/network/if-pre-up.d/iptablesload{.sh,}