Thanks, I will have a look on this.
Independent from that, that there is be a better solution to do my netmap, why is this iface event not called reliably?
Hotplug scripts which get not executed during the boot could cause other problems as well.
For example gets the firewall script also not called in this situation.
root@test-r1:~# logread | grep "Reloading firewall"
No log entry for the firewall (created by /etc/hotplug.d/iface/20-firewall) if this happens with the not-executed scripts during boot.
root@test-r1:~# /etc/init.d/network restart
root@test-r1:~# logread | grep "Reloading firewall"
Sun Jun 21 12:48:45 2020 user.notice firewall: Reloading firewall due to ifup of lan (br-lan)
root@test-r1:~# reboot
root@test-r1:~# logread | grep "Reloading firewall"
Sun Jun 21 12:49:22 2020 user.notice firewall: Reloading firewall due to ifup of lan (br-lan)
After another reboot, on which it did execute my script, the firewall entry was created in the log.
(I suppressed for testing all the executions of iptables commands in my script)
I think it is not solved, since the iface script gets not executed on every boot.