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#11
You've apparently missed the point of my posting. I'm not blaming Microsoft of anything. I'm not blaming the security software of anything, either. And I don't have the problem I mentioned or I'd do some experimenting myself.
I saw the report of a problem that didn't make any sense, realized I didn't know what ipconfig /release and /renew actually do, and wanted to undo that ignorance. I've now done some experimentation, gained a little knowledge, and found that my ignorance was even greater than I supposed.
The /release does have a significant side effect. Since it releases the IPv4 addrs (including default gateway and DNS servers) it obviously isolates the PC from the (IPv4) network. Windows reverts to Automatic Private IP Addressing (APIPA) and gives the adapter an addr in the APIPA range - 169.254.0.1 - 169.254.255.254. So even if the PC could communicate with the router it would no longer be on the router's subnet. This all goes back to normal with the /renew. (I expected Windows to start using a "public" network profile, but it does not.)
The IPv6 addrs were not effected by any of this. Surprisingly, they were also not effected by /release6, but ISATAP tunneling shut down. Ipconfig /renew6 hung for a long time, and didn't seem to do anything except find an IPv6 DNS server ... and caused a complaint from the Teredo tunneling service.
This probably makes sence to someone that really understands IPv6, but that's not me.