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General IPv6 Topics => IPv6 on Windows => Topic started by: cnsh on February 24, 2026, 02:52:33 AM

Title: unreachable from outside
Post by: cnsh on February 24, 2026, 02:52:33 AM
I have set up an IPv6 tunnel, but cannot ping from outside, and cannot access open ports from outside.
Both ping and port scan works over IPv4, but IPv6 doesn't.
I'm using Frankfurt endpoint.
It's not my ISP's issue as they themselves have IPv6 services.
Title: Re: unreachable from outside
Post by: cnsh on February 24, 2026, 02:59:22 AM
Little update.
I knocked all firewalls down and then the port was reachable. (IPv4 host is reachable even when the firewall is up)
Wondering where I can make IPv6 firewall rules follow the ones of IPv4.

+ The IPv6 and Neighborhood Discovery Core Networking in advanced firewall is also enabled.
Title: Re: unreachable from outside
Post by: snarked on February 28, 2026, 12:52:08 AM
In your firewall, do you allow protocol 41 (ipv6) for IPv4 packets?  If not, that's (most likely) the problem.
Title: Re: unreachable from outside
Post by: cnsh on March 01, 2026, 04:38:50 AM
(https://pdrive.xn--wb0bo33d.monster/IPv6%20shit/firewall.png)

I have protocol 41 Core Networking enabled, I have no idea about 41 for IPv4...
Both inbound and outbound protocol 41 rules are set.
Title: Re: unreachable from outside
Post by: cnsh on March 07, 2026, 06:22:48 PM
I could solve the issue by allowing edge traversal on Core Networking protocol 41 firewall rule. And, I have moved my tunnel's endpoint to a physically closer geolocation, Hongkong.
Title: Re: unreachable from outside
Post by: cnsh on March 12, 2026, 09:30:04 PM
I changed the tunnel to london, and this problem reoccurs. Even when I turn edge traversing on. Same issue happens, everything works fine and the port is reachable when the firewall is down, but not when it's up.
Title: Re: unreachable from outside
Post by: snarked on March 14, 2026, 12:55:02 AM
QuoteI have protocol 41 Core Networking enabled, I have no idea about 41 for IPv4...
Both inbound and outbound protocol 41 rules are set.

Protocol 41 has to be allowed for IPv4.  Unless you are also doing IPv6 in IPv6, it need not be allowed for IPv6.
Title: Re: unreachable from outside
Post by: cnsh on March 14, 2026, 06:55:02 AM
(https://pdrive.xn--wb0bo33d.monster/ipv6shit/wf.png)

what do you mean by 41 for IPv4? There isn't a selection for which whether I accept 41 on IPv4 or IPv6. Just a "Protocol 41".
Can you tell me where I can allow protocol 41 on IPv4? redefining doesn't help...
Title: Re: unreachable from outside
Post by: cnsh on March 19, 2026, 03:00:56 AM
minor update. I tried to run a port scan to my server, and accidently scanned port 53, the DNS port. It was open. But the server's other IPv6 port was closed while the IPv4 one open.
Title: Re: unreachable from outside
Post by: cnsh on March 19, 2026, 04:30:41 AM
Brief sum up of my issue:
- IPv6 port stays closed and blocked while the same port number on v4 is opened.
- It is NOT A ROUTER ISSUE. TURNING OFF THE PC'S FIREWALL OPENS THE V6 PORT.
- It is not protocol 41 rule issue. I have already allowed protocol 41 on my firewall, with edge traversal allowed.

Someone please give me a solution, this thing has been bugging me for weeks
Title: Re: unreachable from outside
Post by: snarked on March 23, 2026, 12:38:29 AM
Quote(https://pdrive.xn--wb0bo33d.monster/ipv6shit/wf.png)

what do you mean by 41 for IPv4? There isn't a selection for which whether I accept 41 on IPv4 or IPv6. Just a "Protocol 41".
Can you tell me where I can allow protocol 41 on IPv4? redefining doesn't help...

Set protocol type to IPv4.
Set protocol number to 41.
There are no ports for the protocol.
Allow that.
Title: Re: unreachable from outside
Post by: cnsh on March 25, 2026, 04:41:48 PM
Nope. Setting the protocol number to 41 automatically snaps protocol type to IPv6. There's not even a choice to set a protocol type to IPv4
Title: Re: unreachable from outside
Post by: snarked on March 27, 2026, 01:57:00 PM
Doing protocol 41 in IPv6 yields IPv6 encapsulated in IPv6.  That is not what you want.  You want IPv6 encapsulated in IPv4.
Title: Re: unreachable from outside
Post by: cnsh on March 30, 2026, 01:47:50 AM
YES. So tell me **how**. Please. Redefining doesn't help, mate.
Title: Re: unreachable from outside
Post by: cnsh on April 18, 2026, 06:40:53 AM
slight update.
I tried making a rule both on inbound&outbound to accept any kind of traffic at any kind of protocol, but it still doesn't open v6 port.
Instead, the connection works flawless when I disable the firewall completely from the control panel.

I'm still researching for further solutions. Trying to log the firewall, but the logfile stays at 0KB and completely blank whatever I do. I might try checking that log tomorrow to see if it does record anything at all.

EDIT: I solved the issue by changing the nic's network profile
Title: Re: unreachable from outside
Post by: cnsh on April 18, 2026, 06:55:06 PM
Solved!!!
Changed my NIC's network profile from private to public, now everything works as it should be.
Someone explain why this happens although I have allowed IPv6 traffic on all private, public, and domain profiles.
Title: Re: unreachable from outside
Post by: cnsh on April 19, 2026, 05:22:49 PM
I run a DLNA server from my local, so I need this NIC to be in a private profile.
Someone please explain why this works and how I can make it also work in private profile
Title: Re: unreachable from outside
Post by: cnsh on April 19, 2026, 05:33:43 PM
here (https://pdrive.xn--wb0bo33d.monster/IPv6shit/wf%20inbound.txt) is the exported list of inbound rules set on my server. If it helps.
Title: Re: unreachable from outside
Post by: cnsh on April 20, 2026, 09:48:09 PM
according to this (https://www.reddit.com/r/sysadmin/comments/190tvru/office_http_404_in_avd/) thread on reddit, I deleted IfIso key from HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\RestrictedInterfaces\, and it works on private profile too. Problem solved? No.

Another issue from deleting that comes at some windows features ending up bricked completely. Advanced windows firewall, media streaming settings, and various other stuffs won't start and gets bricked. Is there a way that it won't brick any of the windows services while getting that IfIso removed?
Title: Re: unreachable from outside
Post by: cnsh on April 30, 2026, 04:09:42 AM
I checked everything. From firewall inbound/outbound rules and general firewall settings to registry keys (Ifiso settings and etc). EVERYTHING. Firewall logging won't work (even after restart), and I have no clue how to fix this damn issue.

Thinking that it might be Windows side issue. Will submit a bug report today, even though noone will look into it, I'm enough fed up with this thing.