BIND and UDP tuning

[Lee]

On 9/27/18, Alex <mysqlstudent at gmail.com> wrote:
> Hi,
>
>> Just a wild thought:
>> It works with a lower speed line (at least I read it that way) but has
>> problems with higher speeds.
>> Could it be that the line is so fast that it "overtakes" the host in
>> question?
>>
>> A faster incoming line will give less time between the packets for
>> processing.
>
> No, I actually upgraded from a 65/20mbit to a 165/35mbit recently,
> thinking it was too slow because it was happening at the slower speeds
> as well. I've also implemented some basic QoS to throttle outgoing
> smtp and prioritize DNS but it made no difference.

Has your provider enabled qos?  I'd bet their dropping packets that
exceed qos rate limits would be considered "working as expected".

Which brings up the question of exactly what does SERVFAIL mean?  Can
no response to a query result in SERVFAIL?  Is there a way to tell the
difference between no response & getting a response indicating a
failure?

Lee