Tightened DNS security question re: DNS amplification attacks.
jay at miscreant.org
jay at miscreant.org
Tue Jan 27 21:42:39 UTC 2009
Quoting Matthew Huff <mhuff at ox.com>:
> Given the recent DNS amplification attacks, I've audit and updated our
> authoritative servers. We are using 9.6.0-P1 now. I've been using the cyrmu
> templates, but one thing I see is that the dns queries to the . hint file
> are still occuring and are not being denied by our servers. For example:
>
> 27-Jan-2009 15:00:22.963 queries: client 64.57.246.146#64176: view
> external-in: query: . IN NS +
> 27-Jan-2009 15:00:23.118 queries: client 64.57.246.146#33146: view
> external-in: query: . IN NS +
>
> the named.conf has:
>
> ...
> ...
> ...
>
> view "external-in" in {
> match-clients { any; };
> recursion no;
> additional-from-auth no;
> additional-from-cache no;
>
> zone "." in {
> type hint;
> file "db.cache";
> };
> ...
> ...
>
> since you can't put a "allow-query { none; };" in a hint zone, what can I do
> to deny the query to the . zone file?
>
>
>
> ----
> Matthew Huff | One Manhattanville Rd
> OTA Management LLC | Purchase, NY 10577
> http://www.ox.com | Phone: 914-460-4039
> aim: matthewbhuff | Fax: 914-460-4139
>
Hi Matthew,
I'm using the following with 9.5.1:
view "external" {
recursion no;
allow-query-cache { none; };
zone "." IN {
type hint;
file "/var/named/named.ca";
And my logs indicate that the requests for . IN NS are being denied:
Jan 28 08:40:38 web1 named[12337]: client 64.57.246.146#33453: view
external: query (cache) './NS/IN' denied
Jan 28 08:40:39 web1 named[12337]: client 67.192.144.0#41794: view
external: query (cache) './NS/IN' denied
Cheers,
Jay
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