:: Re: [DNG] My ISP is blocking devuan…
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Auteur: Arnt Gulbrandsen
Date:  
À: dng
Sujet: Re: [DNG] My ISP is blocking devuan.org
Robert Storey writes:
> This problem has been going on for four days, and then suddenly
> about an hour ago, it magically resolved itself. I can access
> devuan.org just fine now.


ns200.anycast.net sounds like an anycast DNS server, which I suspect
doesn't tell you much...Pretend that you have a dozen hosts around the
world, and all listening to the same IP address. That's not easy to
arrange, but if you have a network with a 24×7 NOC and its own AS, you can
talk to other NOCs and arrange it. Connections (and traceroute) will go to
the closest of the dozen.

This kind of thing is perfect for serving high-volume DNS.
f.root-servers.net was the first well-known anycast server, there are many
around now.

It sounds as if one of the ns200 instances, the one closest to Japan, was
acting up and OVH's monitoring didn't catch the specific problem promptly.
Thus, the ISPs closest to the one the bad ns200 couldn't see devuan.org.

I'm more than a little surprised that OVH operates both nameservers using
the same infrastructure. easydns.com, for example, operates similar things,
but takes care to use different anycast operations and even TLDs, so one
point of failure won't kill all nameservers.

Arnt