Lock down Relay and Authentication
Posted on 2007-03-27
I had a domain that was hosted for me by another company with these addresses
I implemented my Exchange 2003 on a child domain and they have these addresses
I changed the public mx record to point to my Exchange IP and I created
<user>@Domain.com addresses for all users in AD. Everything is delivered
perfectly when Exchange is an Open Relay and I allow Anonymous Access but as
soon as I try and restrict my Relay or Disable Anonymous Access only my child
domain email addresses work. From an outsider they receive "550 5.7.1 Unable
to relay for " when sending to <user>@Domain.com but sent from the same
outsider and sending to <user>@Child.Domain.com the email is quick as a deer!
I know spammers will find me, if they haven't already, and use my Exchange to
spam people, so how do I go abouts locking down my Exchange environment?