You might prefer to receive emails that include a real sender in the From field, rather than see the actual email address the notification is coming from.
In Administration > Settings > Emission email address change field setting to following:
Your From Sender <email@example.com> (e.g. Support Company X <firstname.lastname@example.org>)
You will now receive Redmine notifications from a real sender (“Support Company X”), not a plain email address, like email@example.com.