How does ASP.NET Core authentication works with external providers like Google, Facebook, etc.
Authentication - Blog
How to use union types in C# to create typesafe and more expressive return types.
DMARC is a control system and tells the receiving mail server whether to accept an e-mail message if SPF and/or DKIM failed.
With DKIM the sending mail server encrypts the e-mails body and headers and appends the encrypted hash to the e-mail header (DKIM-Signature).
SPF (Sender Policy Framework) tells the receiving mail server whether the sending mail server is allowed to send e-mails with the domain of the sender email address.