I’m in the habit of searching Google for “what is my ip” to see my IP address; they have a little onebox result right at the top that shows it.
Turns out it’s cached. Worse than useless, actively harmful.
At least that’s what it looked like. I searched “what is my IP” today when I was on WAN2, my backup, and saw my WAN2 address. Then I fixed WAN1 so it’d work again and it looked like my router returned to WAN1 from failover to WAN2. But I’d type “what is my IP” and Google still showed the WAN2 address, like the return hadn’t happened. I finally checked on some other site and saw that the failover had happened. A shift-reload on the Google search page did finally show the correct data. All of this sure looks like something is caching the IP address. Maybe it’s related to a persistent HTTP or QUIC session my browser has open?
Every time I do this I have to remind myself https://api.ipify.org/ is the best way to check your IP. Simple text result, a web service intended for this use. Ipify has other tricks too, including an inexpensive geolocation service.