Unbound and EDNS

George Thessalonikefs george at nlnetlabs.nl
Mon Dec 27 13:54:25 UTC 2021


Hi Eoin,

Unless you refer to something specific, Unbound supports EDNS since the 
very early versions (0.4 or so).

Applying arbitrary EDNS options is not something that is supported 
out-of-the-box; you could write your own module (C or Python) to do that.

You could also (ab)use:
	edns-client-string: 0.0.0.0/0 '<ASCII string>'
	edns-client-string-opcode: <EDNS option code>

to set the EDNS option to all outgoing traffic if ASCII is workable for 
you or if you only care about the option code being there (with an empty 
ASCII string). However you cannot dynamically change these options via 
unbound-control IIRC.

Best regards,
-- George

On 21/10/2021 12:30, Eoin Norris via Unbound-users wrote:
> Hi guys
> 
> Quick question. I am using unbound as a simple forwarding server. We had rolled our own EDNS support, but we need to update to the latest .
> 
>   I see that unbound has added some EDNS support in recent releases. What we need is to be able to add EDNS data from another app to each datagram, via the control. This data will be consistent for  the lifetime of the app.  Anyway is this something that is possible now?
> 
> Thanks
> 
> Eoin
> 


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