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Gmail allows users to create custom email addresses on the fly by appending "+keyword" to their email address.

So, "" and "" & "" all point at the same account (

Is there a (reasonably simple) way to configure MS Exchange (any version) to behave similarly?

Bonus: is there an official term for this feature?

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Which version of Exchange? Do you have access to the Exchange System Manager? – Cypher Nov 12 '10 at 20:58
up vote 2 down vote accepted

It's called "SMTP Tags" or "sub addressing" depending on who you speak to. You may find this wikipedia article useful as it talks about this feature in email.

As a practical matter it isn't supported by quite a few email systems for various reasons - some good (or at least understandable), some not so good. If you use it as an anti-spam mechanism (e.g. to track who gives your address away) then be warned that spammers are smart enough to remove these parts from a list of email addresses...

IIRC, exchange doesn't support it and doesn't really have a mechanism for doing so (you could of course add multiple SMTP addresses to a user's mailbox to create a similar effect but this is obviously very inconvenient to set-up and maintain for all concerned).

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Got it - thanks! – Busticated Nov 12 '10 at 21:42

Exchange doesn't have the ability to do this. The address is used as a lookup for recipient mail, which is checked against the address lists stored in the system. A new address would have to be added for each tag you use, which is not long term supportable.

However, there are hooks for third party utilities to provide this functionality. The hooks that AntiVirus/AntiSpam systems use, Transport Agents, could be leveraged by such a utility to strip off the information after the + and add it to a mail header, or whatever needs to be done to it. This would allow delivery of the mail to the end user as the To: address would be correctly formatted for Exchange.

I don't know of any packages that do this, though.

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With enough scripting time and knowledge, you should be able to put something together with the "catchall" mailbox sink for Exchange Server

Sounds like you could add a new email alias to your all of your users like @domain.local Apparently the catchall won't let you forward email to the same domain, to avoid loops.

Then, in the catchall, anything with a "+" sign (or any other criteria) could be re-routed to the user address in the domain.local domain - you might even be able to take that tag and insert it into the subject.

So "" gets forwarded myaddy@domain.local

Haven't done it, but looks like it's possible depending on how much work you want to put into it.

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