Scan with PortScan your Router-IP. Think this should work for you.
Switch scan type to "Scan All Ports". In this case I simply scanned the local host. Change localhost to your Router IP.
Question
I want to check remotely if a specific port is opened on a wifi router. How can I do that?
Do I need to set something on the router side?
I tried using telnet but I get Unable to connect to remote host.
Solution 2
Scan with PortScan your Router-IP. Think this should work for you.
Switch scan type to "Scan All Ports". In this case I simply scanned the local host. Change localhost to your Router IP.
OTHER TIPS
On ubuntu: sudo apt-get install nmap; nmap -vv <router-ip>