I exposed my personal web server to the outside world by opening port 80 for incoming on my firewalls and doing the proper port forwarding. Then I went to whatismyipaddress.com to get my outside IP address to test in Internet Explorer. Using the IP address whatismyipaddress.com gave me (IPv6 it seems) in the IE address text box resulted in IE doing a Bing search with the address. I tried the address in Firefox with address bar search turned off and Firefox gave me "The address isn't valid". I spent lots of time making sure my firewall and port forwarding settings were right, which they were. No matter what I tried, I couldn't get to my web server using that address. Then I went to canyouseeme.org which reported my IP address as a IPv4 address. I was surprised. I thought that IPv4 was no longer in use on the internet. I tried that address in the browser and I immediately got to my website.
Why does my IPv6 address as reported by whatismyipaddress.com not work in either browser when the IPv4 does in both? I thought IPv4 was history on the internet.