reject invalid dns queries

[Matus UHLAR - fantomas]

On 19.01.15 16:14, Daniel Dawalibi wrote:
>Invalid DNS queries : non-existent domains that do not resolve to any IP as
> mentioned in the below example.

you should better not use this definition.

>We are trying to protect our DNS servers from a number of invalid dns
> queries targeting our caching server and originated from different source
> IPs.  Is there any way to drop these requests based on the Query Access
> list from the DNS configuration file (named.conf)?

you can NOT know if a hostname exists before you try to resolve it. After
that, you can't block it anymore.

do you allow recursion for remote clients? (recursion and allow-recursion
statemends) 
Do you allow DNS access from remote clients? (allow-query statement)

Perhaps denying remote clients from even accessing your caching server would
help you with this problem.

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