Hello,

We have exchange 2003, running on a Windows 2003 SBS server. This exchange server provides mail for multiple domains. We are attempting to set up a 'catch-all' mailbox for one of the domains. I've followed the instructions provided by Microsoft here:

http://support.microsoft.com/kb/324021

Having done this the following happens:

    Internal mail routes fine, even accross the multiple domains the exchange server covers.
    External mail to valid addresses on the domain with the catch-all work.
    External mail to invalid address are not routed to the 'catch-all', and return a 550 5.1.1 user unkown message to the sender.

Does anyone have any idea what setting / settings we need to change to get mail sent externally to route correctly to the catch all mailbox?

Many thanks in advance.

I haven't got a 2003 box in front of me at the moment but I think there's a setting in the SMTP virtual server about unknown recipients that needs unchecking.