Dns sometimes fails using Google DNS / automatic dnssec

Yunhong Gu guu at google.com
Thu Nov 15 14:47:02 UTC 2012


Hi, David

I work at Google Public DNS and will take a look at this issue. No
RRSIG should be returned unless the client set the DO bit to ask for
it.

Thanks
Yunhong

On Thu, Nov 15, 2012 at 9:12 AM, MailPlus| David Hofstee
<david at mailplus.nl> wrote:
> Hi,
>
> We've been seeing automatic RRSIG records on Google DNS lately, the 8.8.8.8 en 8.8.4.4. They are not always provided. They cause problems for some of our customers in a weird way I cannot explain. For them these records do not resolve but I cannot reproduce it.
>
> So when I run dig command
>
> dig @8.8.8.8 m1.mailplus.nl
>
> it often provides the RRSIG record (but e.g. the TXT record will not be signed). I've heard that DNS may fall back to TCP and/or may be filtered by firewalls if UDP is over 512 bytes. However, the request is not that long, about 200 bytes if I interpret the answer correctly.
>
> Can someone come up with a good explanation why a tiny percentage of our customers cannot resolve (some of) our domains?
>
> Btw, our nameservers (transip.nl) only provide DNSSEC records if explicitly asked. What is standard here?
>
>
> Thanks,
>
> David Hofstee



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