My next feature I am trying to get working is basic port forwarding to my Synology NAS.  I need 2 ports forwarded to that device (5001, 9901) and I looked at the how-to FAQ (https://www.tp-link.com/us/support/faq/1797/) and either not following correctly or something is just not right.  

The basic premise and concept are fine, but using the app, normally you tell the router to listen on a port and send it to a local device/IP.

So when I goto the app, Advanced -> NAT forwarding -> Port Forwarding I select add a rule.

Service type is custom

Service name - Synology 

Internal IP is where things are just not working.  I select Internal IP, and there I see Use Client IP (checked by default), Use Custom IP, then a block and IP address and a choice to select from clients.  So I select that device, but I can't click Done.  I can click the left (back) button, select the external port of 5001 leaving the internal alone as it will be the same, and on save says Please select an internal IP.

I even went so far as to try and manually enter, but you can see below on that attachment it says IP address must be in the range 192.168.68.50-192.168.71.250!

So I can't even manually setup that route.  I am not sure if I am understanding how TP is doing this as I am used to networking on different hardware, but seems that it should be pretty straight forward.

Thanks.