I saw some similar problems but can't find explanation using this router. Anything I find not work.
I get new ZTE ZXHN H168N router and I setup Port Forwarding for my local server pointed on 192.168.1.100. That server have LAMP with standard ports 21,22,80,111,443,3306. When I setup my Port Forwarding and when I test ports all was open but I still see my router instand my LAMP server or web pages inside it.
My server is connected via LAN to router and I can access via IP but can't access via public IP address or my DDNS.
My old router not have this problems and provider give me this new one because we buy symmetrical connection 20/20Mb/s and this new router break whole infrastructure in my office. Provider's customer support don't know solution and I'm alone ot this.