This blog is an answer to the above questions.
With the migration of customers from OIC Generation 1 to Generation 2, we have changed the underlying stack that sends email from Cloud Notification Service (CNS) to OCI Email Service. With this, the SPF and DKIM configuration previously done will not be valid anymore and these need to be reconfigured to increase the deliverability.
If you are willing to use your own "from" address like firstname.lastname@example.org. You have to follow the below 2 steps.
SPF is an acronym for “Sender Policy Framework”. SPF is a DNS TXT record that specifies which IP addresses and/or servers are allowed to send email “from” that particular domain. A domain administrator publishes the policy defining mail servers that are authorized to send email from that domain. when an email is received the inbound SMTP server then compares the IP address of the mail sender with the authorized IP addresses defined in the SPF record. An example of SPF record for oraclecloud.com is like below. Read the complete article here.
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