[dns-operations] Oddness with Cloudfare authoritative servers

[Adam David]

This does not seem to be a DNS resolution/misconfiguration issue on
Cloudflare's end.

https://172.64.80.1/ provides an error message (as it should) indicating it
is a CloudFlare IP. If you can't see that in a web browser, then the issue
is local to your network.

The main causes that I gather would be:

1. There was a temporary cache propagation issue on CF's network. (Still
not a DNS issue.)
2. Your IT department is using 172.0.0.0/9 or possibly even 172.0.0.0/8
where they intended to use 172.16.0.0/12 (RFC1918 IP space). This would
block access to the netblock belonging to Cloudflare and you would have
difficulty accessing thousands of websites.
                                 Side Note: 172.64.0.0/13 belongs
to AS13335.

You should always start with your IT department.
If you are a Cloudflare customer, contact them directly.
If you are a DeltaMath customer, then you need to contact them directly.

Sincerely,

Adam Vallee



On Wed, Sep 22, 2021 at 4:03 PM Brown, William <wbrown at e1b.org> wrote:

> From: dns-operations <dns-operations-bounces at dns-oarc.net> On Behalf Of
> Erik Stian Tefre
> Sent: Wednesday, September 22, 2021 3:38 PM
> To: dns-operations at lists.dns-oarc.net
> Subject: Re: [dns-operations] Oddness with Cloudfare authoritative servers
>
> > Possibly not a DNS issue at all, but something like this:
>
> > https://community.cloudflare.com/t/revil-ransomware/301435
>
> > (Executive summary: One Cloudflare IP being blocked by a firewall
> because of a different and misbehaving Cloudflare customer who happened to
> serve malicious content from that same IP.)
>
> > Regards,
> > Erik
>
> Interesting.  The real issue I am experiencing is that I am getting
> inconsistent responses from nominally the same authoritative server.  It
> just so happens that when we get 172.64.80.1 as the answer it fails.  I
> would prefer to get the correct answer so students can use the online
> educational resource the district is paying for.
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