External IP address in router UPnP settings Whatsapp – UK Ministry of Defence IP Address?

I was fiddling with my router’s UPnP settings and found this

enter image description here

Why is an external IP address showing here?

I also did a reverse IP search and to my surprise the IP 25.54.27.39 showed "UK Ministry of Defence". I am not in the UK military or on a military base.

Something fishy going on? I have already disabled Upnp.