UPnP is helpful in certain situations where you need a device to poke holes in your firewall for particular services, the most common usage of UPnP in MikroTik is for online gamers who want to achieve an open NAT type for their XBOX One’s, PS4’s and other applicable gaming consoles. Some CCTV systems do offer usage of UPnP for remote viewing. UPnP is seen as a bit of a security flaw because it allows devices to poke their own holes, if a device becomes compromised it could open your network up to a lot of nasty stuff from the web, you should only really use it as a temporary measure whilst you employ a good port forwarding structure or where port forwarding is not possible.
Assuming you have full access to the router, use Winbox to log into it and open up the IP>UPnP window.
Click on the “Interfaces” button and then hit the “+” button to start adding in the interfaces you want to UPnP. You need both an internal and external interface so I always start with internal.
Then you need an external
Once you have both an internal and external interface added, click “Apply” an you’re done!
You will need to make sure that you have the relevant firewall rules to allow the traffic through as traffic hits the NAT table before going through the firewall.