Thank you Marcelo for your advice. I did as you suggested, but still I can’t access the IP cameras from the Internet – I now only get a “Page cannot be displayed”.
I’m pretty sure that the firewall is the culprit, but I’ve just spend the better part of 6 hours googling, adding and deleting firewall rules, changing the forwarding rules, testing… and still it does not work!
Either I’m missing something or ZS can’t do port forwarding. Fact is, I’m about ready to forget about ZS and get another router to do the job.