[dnsdist] Modify EDNS NSID response back to client

Remi Gacogne remi.gacogne at powerdns.com
Tue Oct 26 08:19:51 UTC 2021

Hi Rob,

On 10/21/21 18:13, Robert Schwartz via dnsdist wrote:
> I'm trying to find a way to add a suffix to an existing NSID string 
> response coming back from a backend server. My use-case is to be able to 
> know, not only which backend server responded to the query (that's in 
> the backend response), but to also know which DNSDist box handled the 
> proxy request. The DNSDist boxes are behind an anycast IP (aws global 
> accelerator) so it's not always clear which DNSDist box handled a given 
> request.
> Is this possible and how would I go by implementing this?

I'm afraid dnsdist doesn't offer any way to do that easily, short of 
parsing and rewriting the whole DNS payload in Lua by yourself.
As a rule we tend to avoid adding code to alter responses, as we believe 
dnsdist is not really well-suited to that job.
In your case I see how it might be difficult to do that in the backend 
itself, of course :-/

Remi Gacogne
PowerDNS.COM BV - https://www.powerdns.com/
-------------- next part --------------
A non-text attachment was scrubbed...
Name: OpenPGP_signature
Type: application/pgp-signature
Size: 488 bytes
Desc: OpenPGP digital signature
URL: <http://mailman.powerdns.com/pipermail/dnsdist/attachments/20211026/837a26ce/attachment.sig>

More information about the dnsdist mailing list