An Outlook user had problems assigning tasks to users outside their company Exchange Server:

We use Exchange 2010 and the administrator configured it to not send RTF to Internet addresses. While it solves the problem of attachments getting encoded as winmail.dat files, the unintended consequence is that we can't assign tasks to contractors who don't have local addresses. What can we do?

The Exchange administrator can create a Remote Domain for the contract's email domain and set it to "let Outlook decide" the message format for all messages sent to this domain. Along with controlling the email format, the administrator can also configure Exchange to allow (or block) Out of Office messages and read or delivery receipts or non-delivery report to the domain.

It's accessed through the Exchange Management Console Organization Configuration > Hub Transport > Remote Domains or using the following cmdlets.

To get a list of all remote domains where TNEF is disabled:

Get-RemoteDomain | Where {$_.TNEFEnabled -eq $false}

New-RemoteDomain -DomainName thedomain.com -Name thedomain

Set-RemoteDomain -Identity thedomain -TNEFEnabled $true

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Last reviewed on Apr 10, 2012