Cloudflare problems with IPv6 range visiting any website

I am having problems visiting other Cloudflare-protected websites, but only from my allocated global IPv6 /48 prefix. If I disable IPv6 locally and force the browser to use only IPv4, everything works as normal.

Is there a way to check ‘reputation’ for IPv6, like there is for IPv4 addresses (which I already checked)? I searched but couldn’t find one.

The first problem, going on for some weeks now, is prolonged Cloudflare browser checks on every site, even when I’ve visited that site multiple times that day, and far too frequent capchas. The second problem which I’ve just noticed is being blocked completely from accessing some sites, again only when using an IPv6 address from my range. Switch to IPv4 and everything works.

Note that the IPv6 prefix is only used locally, with some PCs and other devices. None have been compromised, no viruses, etc… It was the first thing I checked. The problem happens on all the PCs and in a clean VMware Windows10 client I set up just to test all of this.

I’ve read the usual list given here of things to do to work around problems caused by Cloudflare, but clearly there should not be a problem in the first place.

I put my IPv6 address in at https://www.projecthoneypot.org/search_ip.php and it accepted it.

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I did try that, but it rejected the IPv6 address so I thought it only worked for IPv4. I just tried again and it worked, thank you. Odd. Anyway…

I passed, again (“We don’t have data on this IP currently.”)

So that’s not the issue then. I’m still getting the problems using my IPv6 prefix on Cloudflare sites, even with Privacy Pass installed (very reluctantly - at least I can get rid of it now).

Well, still no reply to my support ticket.

I’ve confirmed by testing that it is the entire /48 prefix which is being blocked. If I change to another prefix I have available (a /64 also from Hurricane Electric) everything works. Change back and I’m blocked again. Unfortunately I need to use the /48 for local subnets.

It seems I’m just being arbitrarily blocked from accessing much of the internet, on a previously working and legitimate IPv6 range.