Is it possible to schedule email forwarding start/stop in Office 365? I see a way to enable/disable in both the Office 365 and Exchange sides, but no way to schedule it. Exchange mail flow rules don't have a date/time criterion.
I could write a PowerShell script to forward email to run as a scheduled task, but that requires separate credentials to connect that I can't/won't store on disk.
You can use this method to convert the password to a secure string so it doesn't have to be stored on the computer that is running the script: https://blogs.technet.microsoft.com/robcost/2008/05/01/powershell-tip-storing-and-using-password-credentials/
It turns out that you can, in fact, set a date/time component on mail flow rules.
This may be dependent on what kind of Exchange you have, but when creating a mail flow rule, the date/time is under "more options". You can then set it to either redirect the messages or add a recipient to the to/cc/bcc fields.
There are three components that can accomplish this in Exchange:
Exchange Transport Rules Mailbox Autoreply Configuration Inbox Rules
Of these, only Exchange Transport Rules and Mailbox Autoreply (Out of office) Configuration allow setting a start/stop time. Neither of these options offer a recurring schedule capability, this is a one-time on/off schedule.
Inbox rules (configurable through Outlook client or OWA) do not allow a schedule to be set. Users could toggle the rules on and off manually on a schedule, however.
