[Pdns-users] pdns recursor edns-client-subnet caching problems

Remi Gacogne remi.gacogne at powerdns.com
Wed Aug 2 09:02:10 UTC 2017

Hi Shawn,

On 08/02/2017 08:47 AM, Shawn Zhou wrote:
> Sorry. I meant the authoritative nameserver did respond with the correct answer. 

The authoritative server answers with a EDNS Client Subnet scope set to
0 when we send a query with a source set to, meaning that
we can cache the answer and use it for any source:

$ dig @ns1.insnw.net +subnet= morpheus-ien.insnw.net

; <<>> DiG 9.11.2 <<>> @ns1.insnw.net +subnet=
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 41118
;; flags: qr aa rd; QUERY: 1, ANSWER: 3, AUTHORITY: 2, ADDITIONAL: 3
;; WARNING: recursion requested but not available

; EDNS: version: 0, flags:; udp: 4096
; COOKIE: b560d095f78df047eb13a9a85981941eb2b38c5376e87bb2 (good)

Once this answer is in our cache, we will use it until it expires and
won't look for most specific answers, regardless of the ECS value of the

Remi Gacogne
PowerDNS.COM BV - https://www.powerdns.com/

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 488 bytes
Desc: OpenPGP digital signature
URL: <http://mailman.powerdns.com/pipermail/pdns-users/attachments/20170802/262cd6f8/attachment.sig>

More information about the Pdns-users mailing list