Occasionally you might need something on the inside of your network, like a monitoring machine or copier, to be able to anonymously relay to external domains through Exchange 2010.
We’ve used 192.168.1.1 for our Exchange Servers IP and 192.168.1.23 for the machine that needs to email.
You’ll need to setup a receive connector:
New-ReceiveConnector -Name “Anonymous Relay” -Usage Custom -PermissionGroups AnonymousUsers -Bindings 192.168.1.1:25 -RemoteIpRanges 192.168.1.23
Then you’ll need to allow this to send to external domains:
Get-ReceiveConnector “Anonymous Relay” | Add-ADPermission -User “NT AUTHORITYANONYMOUS LOGON” -ExtendedRights “ms-Exch-SMTP-Accept-Any-Recipient”