The Hub Transport server has 2 Receive Connectors that are created by default:

The Default RC accepts inbound connections on port 25 and the Client RC accepts connections from remote clients on port 587. Whilst I understand the purpose of the Default RC I’ll need to do some more research into when and how the Client RC is used.

I looked at the properties of on the Default RC but couldn’t see anything that might help me. There are various options available for authentication but none that seemed to allow anonymous access.

A little more digging led me to the Exchange Management Shell and a Cmdlet called set-ReceiveConnector.

With the following command line I managed to get my Default RC to accept email from non-authenticated sources. 

set-ReceiveConnector -identity "Default LABCRWEXHT1" -PermissionsGroups AnonymousUsers

The moral of the story? Get used to the Exchange Management Shell as there’s no avoiding it!

[tags]Exchange 2007[/tags]