nargzul I’m not a prof in IP related questions. But AI tells me:
This is expected behavior.
Port 443 (HTTPS) is used by the router itself for its management interface.
Traffic to ports that are used by the router (like 443 for HTTPS or 80 for HTTP) is handled locally by the router and never forwarded, even if a DMZ host is configured.
The DMZ only receives traffic that is not already claimed by the router.
More detailed explanation
Even though the user manual states that “all traffic without a rule is forwarded to the DMZ host”, there are important exceptions:
1. Router management ports always have priority
Most routers reserve certain ports for their own services, especially:
Incoming traffic to these ports is terminated by the router itself, before NAT or DMZ forwarding is applied.
2. DMZ ≠ “forward absolutely everything”
A DMZ is effectively a catch‑all NAT rule, but only for:
ports not used by the router
traffic not explicitly blocked
traffic not reserved for management or system services
So the DMZ rule does not override:
3. This is a security design choice
Allowing DMZ to override port 443 would expose the router’s admin interface to the internet or make it unreachable for management — which is why vendors block this by design.
Greetings
Daniele
