Ok, here's an odd one. A while back I updated to the latest Tomato - I was way behind - I had no idea new versions had even been released in the past few years.

I'm pretty sure I reached the web UI after the update, but lately I can't get it to come up - tried multiple browsers on multiple machines.

The router is being used only for routing, including DHCP, DNS. It's otherwise working properly, handing out IP addresses, routing traffic out to the internet via connected cable modem on the WAN port, etc.

Just can't connect to the web UI at the router's IP address. Thinking maybe the IP was reset to some default, I checked that the IP address is what I expect it to be and reported as the Gateway/Router on every system connected to it.

Odd.