So I have 2 systems that are connected to an IPv6 setup router. For an older game UT99 for local network play which only supports IPv4, I set both systems to static IP Addresses under the IPv4 configuration of the network adapters. There is a setting for IPv4 and IPv6.
So with IPv4 configured the local game play for hosting UT99 works no problems. I set the IPv4 to 192.168.55.10 and 192.168.55.11 for the 2 computers.
And on the one computer I without thinking went to my browser and it was working and I was like.... how am I getting out to the web when i just set these to static IP's with no gateway? It appears that the network adapter can have a dual configuration that i was not aware could be done where the IPv6 still was serving up a connection so that you could surf the internet as well as play the game locally on a different network IP. My IPv6 network addresses resolve to 192.168.0.100 with subnet of 255.255.255.0 and gateway of 192.168.0.1
At first I thought this is really cool because I can set IPv4 for the local game needs and set IPv6 to obtain a dynamic IP from DHCP lease and never have to mess in there again with switching back and forth. But when I went surfing the web it seems as though some websites had no problem with this setup and others werent happy with this. Facebook, Yahoo, Google, and Youtube had no problems with this setup however Steam said I was offline and when going to a bank website it acted as if i was offline.
So I thought ok what happens if I flush my DNS Cache maybe its working because DNS Cache has some stuff stored and so I flushed my DNS Cache and then tried again and same result i can get to some websites and they worked without any problems yet Steam said I was offline and the bank website wouldnt even show the home page for the bank.
So I flushed the DNS cache and rebooted the computer in case somehow its cached elsewhere and upon bringing it back up still same results. So I am confused how some sites work fine and others dont when I am pretty sure I wiped the DNS cache so it must not be using that.
Its almost as if some websites and software that connects over the network is working through IPv6 and others that see IPv4 connection with no gateway are getting roadblocked by the IPv4 configuration.
I took networking like 20 years ago in college and I thought IPv4 and IPv6 was you have a network adapter set up as one or the other and not both. I have seen before virtual connections where a network adapter can simulate a virtual network connection through a single NIC but I dont see that happening here or if it is not sure where to find that. Usually you would see that when you perform IPCONFIG/ALL.
It would be cool if I could set a rule for IPv4 to work for local lan gaming and everything else use IPv6 connection, but it seems like some stuff is still using the IPv6 and some stuff is trying to use the IPv4 and not sure where to control that.
Lastly I tried this with a Windows 7 64-bit system as well as my Windows 10 64-bit system. Initially I was on my Windows 10 system and thought maybe its a feature of 10 that is allowing for this oddity, so then I turned on my Windows 7 system and set it up the same and got the same results, so the ability to i guess have IPv4 and IPv6 running side by side on a single network adapter goes back as far as at least Windows 7 which I never knew.
When wanting to have 2 network connections of different networks I have always run dual network adapters and had one set to obtain for IPv4 and the other with a static IP address on its own network also IPv4. My brother gave me his old router which was set up for IPv6 and I never went in and reconfigured it because he too has Vonage and no other port forwards etc so I was able to drop it into place and use it without configuring it. I have for years used IPv4 up until this router which replaced my cooked DLink.