IO domain DNS failure

.sh and .ac are also run by the same folks - looks like there are issues with those tlds as well.

It looks, the the problematic nameserver "ns-a4.io" is down. So, the problem should be disappeared...

At the same time, it looks, there is only one "ns-a3.io" nameserver working for IO domain, at now...

I recieved this reply from nic.io support a few minutes ago: http://imgur.com/a/wV2Kk

AWS response:

Hello,

Some customers have reported intermittent resolution issues with .io domains. We can confirm that Route 53 DNS services are operating normally at this time and these issues seem to be related to the .io top-level domain provider.

We've investigated the issue and are primarily seeing incorrect responses from two of the .io nameservers: ns-a4.io and ns-a2.io. These nameservers are returning NXDOMAIN intermittently for domains that do exist. As a result, once a resolver receives the erroneous response, it will cache the non-existence for the negative TTL, which for .io is set to 3600 seconds (1 hour).

One suggestion we have is to increase the TTLs for your domains in Route 53 so that the resolvers cache DNS answers for a longer duration.

Best regards,

(Customer support rep name redacted)

Amazon Web Services

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For those interested, we wrote a blog post about single points of failure with DNS last Friday when the Dyn attack happened. Our strategy ensures our customers are mostly unaffected by issues like this. See https://blog.ably.io/routing-around-single-point-of-failure-...