[Rspamd-Users] Where to set c= regarding DKIM signature?

[Vsevolod Stakhov]

On 12/04/2021 18:55, Michael Grimm wrote:
> Hi
> 
> I wonder where a DKIM signature's canonicalization flag c= is defined? And please note, that I am a newbie regarding DKIM, still.
> 
> My signature shows c=relaxed/relaxed but I cannot find a way to alter that to e.g. c=relaxed/simple. I do have the feeling that this might be achieved in the dkim_signing module. But I cannot find canonicalization mentioned in that module's description[1] at all.
> 
> Thanks in advance and with kind regards,
> Michael
> 
> [1] https://rspamd.com/doc/modules/dkim_signing.html
> 

Rspamd always use relaxed/relaxed canonicalization for signing as other
types of canonicalization are almost all the time broken by design and
are almost all the time misused by people who doesn't understand how
that works and why their signatures are all broken after that.
Curiously, ARC has removed all but relaxed/relaxed canon by just these
reasons.

tldr; use relaxed/relaxed as suggested and allowed by Rspamd as it is
the most proper way to do DKIM signing.