I have a single 2013 Exchange server setup. I had a request to prevent internal users from being prompted to send read receipts on emails that originated from outside our organization. After researching, I created a rule in Exchange that strips 'Disposition-Notification-To' from the message header if the email is received from outside the organization.
I tested and confirmed with this rule in place, internal users are not prompted to send a read receive to an email they received from outside our organization.
However, what I just learned is this rule also prevents the outbound deliver of Out of Office replies. So, if an internal user sets Out of Office in Outlook and receives an email from outside the organization, the sender never receives the Out of Office reply. I can disable the Exchange rule and now Out of Office emails work correct.
I compared the message header line by line with the rule enabled and with the rule disabled and there is not a single instance of 'Disposition-Notification-To' on emails that do not request a read receipt, so why is the Exchange rule blocking outbound Out of Office reply messages?
Any help would be greatly appreciated.
Thanks,