I have set up receive connector on my Exchange 2010 server to receive email from my Nagios box. I have an external email address in my contacts for nagios to convert emails to text. It seems exchange is refusing to relay mail to an external address but it will relay fine if the address is internal. Are there any other places to look for settings besides the hub transport rules? I also have the receive connecter set up for anonymous login. Any ideas?
Assuming you've created your internal receive connector properly (locked down to Nagios IP) you need to run this command:
Get-ReceiveConnector RelayConnector | Add-ADPermission -User “NT AUTHORITY\ANONYMOUS LOGON” -ExtendedRights “ms-Exch-SMTP-Accept-Any-Recipient”
This will enable the specific permission that enables an open relay. This is disabled by default on all connectors created.