Cloudflare reverse DNS SERVFAIL, normal?

David opendak at
Mon Aug 29 21:13:50 UTC 2016

On 2016-08-29 2:46 PM, Jeremy wrote:
> We're seeing a huge uptick in reverse dns lookup failures across an app,
> 99% are all for Cloudflare ip addresses.
> Instead of seeing a PTR or NXDOMAIN we're getting back SERVFAIL.
> Does anyone know if this is a standard response from them? Do they not have
> reverse DNS setup for their networks?

Got an example range? All the ones I'm checking here seem fine.

> Trying to narrow this down to see if it's a result in a change in how our
> application handles these errors or if there's an issue going on with
> cloudflare's DNS setup.
> Thanks!
> Jeremy

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