Setup anonymous relay, exchange 2010

Open exchange manager, go to server configuration, hub transport, add new receive connector. Name it relay, in the next window remove the ip settings and add the server ip address, the next window add the devices you want to allow relay from. Once the connector is created, open the connector and choose permission groups and select anonymous. Then you need to run a command from the shell: Get-ReceiveConnector "Relay" | Add-ADPermission -User "NT AUTHORITY\ANONYMOUS LOGON" -ExtendedRights "Ms-Exch-SMTP-Accept-Any-Recipient" thats it.