Hello, I recently deleted the default administrator mailbox, did I do wrong, will that impact in any way to my organization, or will it impact on the isa/forefront tmg publishing rules?

It shouldn't affect the operation of Exchange. I would probably mail enable the account though. Exchange doesn't have a "default" mailbox - it simply mail enables whatever account was used to install Exchange. Simon. Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

Thanks Simon