So I have an interesting little problem I'm looking into for one of our clients --

They're in an Exchange environment. First, the user set his Outlook to forward his mail from his address to another internal email address. No problem. The new mail enters his inbox briefly, then immediately passes on to the forwarded address. Then, he changed it to forward to an external email (his hotmail address in this case). This time, the new mail comes in, and nothing happens; it stays in the inbox. So he tried to send it manually, and it does move into the Sent Items folder, but it never arrives in the destination inbox. He's tested this with several different external email accounts (hotmail, yahoo, and charter), and he experiences the same problem each time. So evidently his mail will only successfully forward to internal email addresses.

He noted that they had a problem with people forwarding email too often a couple of years ago. He said that he suspects that perhaps whoever resolved that problem back then may have set some sort of restriction in Exchange to prevent them from forwarding anything to external email addresses. However, he says he checked all the Exchange policies, and everything is on a "low" setting.

So what I did was tinker around with forwarding in Exchange. I'm new to Exchange, so I'm literally learning as I go here, but I managed to create a contact object in AD Users & Computers that contained his hotmail address, then set his user account in AD to forward all email to that object. That worked.

However, that's also not what he wants. He wants to be able to set up forwarding from his Outlook client instead of having to go through the Exchange server every single time, so turns out there was no point to all that tinkering I did anyway.

So any ideas? Could there be a setting in Exchange somewhere that's preventing users from setting up external forwarding from their Outlook client aps? Or what else could cause this issue where they can forward inside but not outside?