Say I have setup an SES domain (identity) called example.com. It seems advisable (for best deliverability) to create a custom FROM domain. This must be a subdomain of the main domain (according to SES), so say I choose notifications.example.com.
When I do that and then send test emails to some validation tools, they complain that there is no DNS A record for notifications.example.com. Is that really necessary? Is there actually supposed to be some service/listener at notifications.example.com?
Thanks.
You will need to create records for the Custom MAIL FROM domain, such as:
MX | notifications.example.com | 10 feedback-smtp.<region>.amazonses.com
TXT | notifications.example.com | "v=spf1 include:amazonses.com ~all"
As stated in the link here about Custom MAIL FROM Domains in SES
Although to your question, you do not need an A record (for the notifications.example.com domain) in order to use Amazon SES in this intended way. Email validation tools may complain about needing certain records although they may not understand the use case.
I hope this information helps! :)