Short post to describe some interesting behaviour I noticed in Exchange 2013 EAC.

If you match a rule such that “Apply this rule if…¬†The recipient is…” and you choose a single alias of a mailbox, you’ll see only the alias selected in the Rule dialog box:

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‘mcf’ has an alias named ‘captainkirk’

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‘mcf’ has an alias named ‘captainkirk’

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‘mcf’ has an alias named ‘captainkirk’

However, when you save the rule, close the dialogue and reopen it, you’ll see that the entire mailbox is now matched:


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‘mcf’ has an alias named ‘captainkirk’

I assume that this is a well-known piece of Exchange information – that messages to a mailbox’s single alias cannot be rejected while allowing messages to the mailbox’s other aliases – but it took me by surprise as it was not what I expected. Sure enough, all messages to the mailbox using any alias were rejected when I tested this.

Of course, I realized this a day later, wondering why I wasn’t receiving¬†deliveries… Oops.