Yes, you can use the IP address or the resolved domain name. Using an IP address directly would bypass any DNS issues. The device would need a static IP address instead of a dynamic IP though or you would need to keep updating occasionally.

As usual, I should have been more specific. The answer that I wanted seems to be:

Yes, type "http://###.###.#.# " in the URL field.

Then listeruk's input is also helpful

You can use the IP address or the resolved domain name. Using an IP address directly would bypass any DNS issues. The device would need a static IP address instead of a dynamic IP though or you would need to keep updating occasionally.

No need to type in http:// as Firefox will add it automatically - just the ip address should do it. Glad you got sorted out.