DKIM, Gmail and emails sent from both code and outlook -

i have business email address: orders@mybusiness.com.

i use send order confirmation emails thru variety of different systems, 1 of .net web app sends emails thru aws ses. there 2 other systems send out emails automatically using same email address via smtp.gmail.com.

i use email address locally outlook manually send emails, , allow people reply directly order notification emails.

i notice aws ses emails come gmail little tag - 'sent via amazonses'. more or less understand why there , how rid of setting dkim stuff.

what don't understand how adding dkim record thru aws effects local setup outlook , smtp.gmail.com. create multiple dkim records? 1 thru aws ses, , 1 thru gmail?

dkim keys have notion of 'selector'. selector identifier particular dkim key domain used sign message. allows multiple dkim keys defined domain, , hence allows multiple independent senders sign messages using dkim.

the corresponding dkim key record in dns can found at

<selector>._domainkey.<domain> 

google (gmail) typically uses selector 'google'. example above, dkim key record gmail published at

google._domainkey.mybusiness.com 

other signers use different selectors, allowing publish multiple, non-conflicting keys.