I'm trying to send email to an outside vendor via an intranet server inside my domain. I've created a receive connector on my exchange server using frontend transport and custom type. Exchange users and anonymous users in the permissions group. Scope is set to the specific web server IP address sending the mail to the relay server. I can send mail to any inside user on exchange.
I added the Get-ReceiveConnector -Identity "Server\RelayConnector" | Add-ADPermission -User "NT AUTHORITY\ANONYMOUS LOGON" -ExtendedRights "ms-Exch-SMTP-Accept-Any-Recipient" at the exchange power shell prompt successfully.
Still no love. Did I miss a step please?