Hello everyone, I was hoping that someone would have an idea on how to disable mailbox lookups. What I have been trying to accomplish is setting up a catchall mailbox on our Exchange 2013 CU1 server. I have my rule all setup and have disabled, or so I thought, recipient lookup with the command "Set-RecipientFilterConfig -Enabled $false". After that is done I went ahead and restarted the MSExchange Transport service. With all that set, whenever I send an email to a nonexistent email address all I get is an NDR back. If anyone has some insight on what I am missing I would appreciate the assistance. 

Hi,

What do you mean by saying "disable maiblox lookup" ?

Would you take an example ?