Comcast residential DNS contact

Jared Mauch jared at
Wed Dec 3 17:58:20 UTC 2014

> On Dec 3, 2014, at 10:45 AM, Stephen Satchell <list at> wrote:
> No.  When I've been victim of DNS amplification attacks, the packet
> capture showed that the attacker used ANY queries.  Legit ANY queries on
> my recursive servers?  Damn few.  So I block.  Not so on my
> authoritative servers, where ANY queries on the domains I host zone
> files for have not caused any problems, for anyone.
> Another thing I did was slow down the port for my recursive DNS servers
> to 10 megabits/s.  That means that my upstream link can't be saturated
> by DNS amplification.  Oh, and I rate-limit incoming queries to my DNS
> servers by IP address range -- an attack from one subnet won't affect
> queries from other parts of the net.  Queries from my IP address range
> have a high cap; J random IP addresses have a lower cap.

You should not filter the any queries, perhaps you want to TC=1 them.  I
created a patch for bind for this purpose.

I’ve seen many of these attacks, they will use MX/TXT/A and other records.

You may want to look at some of the public resources for this, e.g.:

is a good one and for the git lovers:


- Jared

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