sfx2000
Part of the Furniture
That's exactly the problem he has, outgoing traffic to TCP/443. He wants to connect back to his home VPN server. It's not blocked by his ISP because it works with his previous router. In my experience ISPs tend not to block 443 otherwise features like remote cameras or Asus' AiCloud or their phone app wouldn't work.
Yeah - wonder if the ISP has implemented application layer firewalls - some of the newer firewall appliances do look at the traffic itself - e.g. HTTPS over TCP/443 is distinct compared to OpenVPN traffic over the same port.
Unusual to see this at the ISP level, more commonly seen in the enterprise space...