Using CNAME for _domainkey (DKIM)

[Danilo Godec]

Hello,


apparently one shouldn't use CNAMEs for 'delegating' _domainkey records 
to another DNS server, but I see that some email service vendors use 
that - they have their customers add a CNAME pointing to their TXT 
record (one recent example that I was dealing with is atlassian.net 
(https://accessplanit.atlassian.net/wiki/spaces/HG/pages/417005970/SPF+DKIM+SMTP+Prevent+your+system+emails+being+caught+by+spam+filters) 
- probably so that they can rollover their DKIM keys without their 
customers needing to do anything.


I know that CNAME records can clash with other essential (MX, A, ...)  
records, but since a _domainkey subzone is quite specific and unlikely 
to be used for anything else, this should still work, right?

Or should I consider this an absolute 'no-no' and have my 'customers' 
add the complete TXT record?


     Regards,

     Danilo