Thank you for the help, futuretech.
I have Windows 7 Home Basic SP1 on my computer.
As to trying the beta build, I do not feel like I am up to that: too much hassle, very high chances that my computer becomes dysfunctional and/or the security becomes breached. I already had a lot of troubles updating to the current build. So if I am to update again I would rather wait for a stable build where all the issues are resolved.
Also, I do not have any other computers in the network that I can access.
As you suggested, in the Stealth Ports task I chose “Block all incoming connections”, then I went to Online IPv6 Port Scanner and Firewall Tester, but the web page said:
“The request for this page was made using an IPv4 address and so your machine cannot be tested. Your machine may have accessed this page using IPv4 if your DNS configuration is broken or your browser or DNS service does not correctly prioritise IPv6.”
I also have tried another site: http://test-ipv6.com/, below are the test results:
They do not make much sense to me.
Now things are getting weirder and weirder.
Today in my Network Connection properties I turned off TCP/IPv6.
But I still observe IPv6 connections.
All the following is done with IPv6 disabled in the Network Connection properties window.
The command ping -6 google.com works, albeit the round trip times are rather high.
The IP address is 2a00:1450:4010:c0a::65, and it changes from time to time.
In COMODO Firewall I created a firewall rule for ping.exe to block a single IPv6 address 2a00:1450:4010:c0a::65:
Now, when I type in the Command Prompt ping 2a00:1450:4010:c0a::65 the connection is blocked, no packets are received.
In the Firewall Events Log I see the corresponding event of blocked ping.exe connection.
When I create the same firewall rule for Firefox browser
Firefox still can connect to this IPv6 address
When I make a firewall rule to block all connections for ping.exe, then ping can not connect to any IP,
and neither ping google.com nor ping -6 google.com work.
The blocking of both of these connections is recorded in the Firewall Events Log.
When I make the same firewall rule for Firefox to block all connections, then Firefox becomes unable to connect to any IPv4 address, but it still can connect to IPv6 addresses. And in the Firewall Events Log only the blocking of IPv4 connections is recorded, while the IPv6 connections do not show at all.
When I make a global rule to block all connections for all programs, then neither ping nor firefox can connect to the Internet.
But in the Firewall Events Log only blocking of IPv4 connections is recorded.
When I make a global rule to block a single IPv6 address 2a00:1450:4010:c0a::65,
then ping.exe can not connect to that IP, and the blocking is recorded in the Firewall Events Log.
But Firefox still can connect to that IP and no records appear in the Firewall Events Log.
So, the conclusion for now is: the IPv6 blocking works for some programs, like ping.exe, but it does not work for programs like firefox.exe and cmdagent.exe. The latter two, I believe, belong to the group of “safe applications”.
Also, ping.exe connects through ICMPv6, while firefox and cmdagent through TCP.
Does this make any sense to you?
Also, why is the IPv6 connectivity fully functional on my computer, even though I disabled it in the Network Connection properties?