Can you show us screen shot from Status tab?

Thank you for your quick reply.
I've attached a screen shot of the Status tab.





As an aside, I've noticed that accessing the modem/router admin site on 192.168.1.1 times out regularly. It can take me quite a large number of retries and reboots before it opens. Could this be related in any way, or should I open that as a separate thread?

Steve

No further input into my query?

Interface Setup->Internet tab yet

Here you go, thank you.







Steve

I'm not sure for 100% but I think that is problem with your IP address on the WAN port. It isn't public IP address. You have to contact with your ISP and explain this case.

I'm sorry, I don't understand. That IP address seems to be a public address to me. My private addresses are all 192.168.1...
What makes you say it's not public? It's the address allocated to me by my ISP, and is therefore outside my control.

The new address today is 171.248.135.11
Should I be able to ping that address from my home computer? I can ping the gateway, but not that address.

I said - You have to contact with your ISP and explain this case.

I am an English native speaker and hold a Master Degree in Applied Linguistics, so I was able to read what you wrote with ease. There was no need to repeat it. If you don't want to assist me then simply ignore my post just as it seems the TP-LINK staff and experts have done so far. That said, I appreciate your effort to respond. I asked questions for clarification, as I also have a background in IT (just not deeply into networking) and what you wrote does not match my limited understanding of WAN addresses.
So, I will rephrase my unanswered questions:

Why do you believe that 171.248.135.11 is not a public IP address?
Should I be able to ping that address?

For the record, calling my ISP is not as simple as you may think. I live in Vietnam, and even using my basic understanding of the Vietnamese language, neither technicians nor service staff understand the concepts of "investigate, explain and resolve". As far as they are concerned, if the router is physically installed and I can load web pages then they have done their job.