Hope these answers help you. P.S. I didn’t see your previous reply so you’ve actually answered one of the questions yourself.
No alert for “DNS server settings changed” when change access points (AP)
@Ken_GlassWire has probably pinpointed the most obvious reason why there is no alert for change of DNS server because there is no change when both APs use the same DNS server IP address.
You can tell if GlassWire has registered the change of AP by checking the Network view.
No alert when change WiFi band
Multi-band WiFi can be configured in several ways. Some configurations will produce alerts in GlassWire but the most common configurations will not because there is no change to the DNS address and even the IP address.
GlassWire is looking at the logical details which does not include the wireless band. In your case, the wireless bands correspond to separate devices with different MAC addresses so GlassWire shows this in the Network view. But there is no alert to show a changed MAC address unless the IP address also changes.
It would be good if GlassWire did show changes to the type of Internet connection, e.g. cabled versus wireless, 2.4GHz versus 5GHz wireless. That would avoid some of the absurdities like being told a remote host is not connected when it is. In the screenshot, GlassWire tells me that the same host has connected twice then it has disconnected. I had actually connected the remote computer through Ethernet and WiFi at the same time. The network adapters had different IP addresses (Ethernet 192.168.1.63 and WiFi 192.168.1.73) but GlassWire doesn’t pick that up:
Alert for “DNS server settings changed” shows IPv6 address when only using IPv4
Why do you get an alert showing the default IPv6 local-host address which is prefixed with fe80::? Technically we should say fe80::/64. The address prefix you see, fec0::, is an old standard.
My understanding is that the assigning of the default local-host results from the auto-configuration capability of IPv6. It assigns a default IPv6 address in the absence of a DHCP server. GlassWire picks this up before you get an authorized connection to the new AP and are assigned an IP address by the DHCP server for that AP. The correct IPv4 address is then assigned
Technically, you can turn off IPv6 but Microsoft actively recommend that you do not. In some situation troubleshooting a problem might require turning off IPv6 but this can introduce other issues because Microsoft has not tested Windows with IPv6 turned off. See “IPv6 for Microsoft Windows: Frequently Asked Questions”:
FYI, fec0:: is the deprecated and therefore superseded local-host address equivalent to fe80::. The old address usually means that you are using an old version of Windows, probably Windows XP because I think the behavior changed with Vista. An IPv6 local-host is assigned to ensure that when only IPv4 is being configured manually then IPv6 DNS queries are not generated. It used to be the case, and probably still is, that if both the IPv4 and IPv6 DNS addresses are local-host then only an IPv4 DNS query (record A) is generated and no IPv6 DNS query (record AAAA).