Troubleshooting Cerberus Email Sending Issues via Exchange SMTP (Enabling Anonymous Relay in Exchange Server)

Troubleshooting email Relay Issues on Exchange Server:

If you encounter problems sending emails outside your domain, your Exchange server may lack the proper setup for relaying emails. Below are straightforward steps to add a connector allowing email relaying outside your organization:

1. Create a New Receive Connector:

   • Name it as desired (e.g., TEST) and choose "Custom" as the intended use.

2. Local Network Settings:

   • Keep it as is, allowing it to listen on all local IPs on port 25.

3. Remote Network Settings:

   • Clear 0.0.0.0-255.255.255.255 and add the IP address of the remote server needing relaying permissions.

4. Connector Properties:

   • Once created, access the properties of this connector, go to the "Permission Groups" tab, and add "Anonymous Users."

5. Cmdlet for Anonymous Relay:

   • Execute the following cmdlet to permit anonymous users to relay via this connector:
     
     Get-ReceiveConnector “TEST” | Add-ADPermission -User “NT AUTHORITY\ANONYMOUS LOGON” -ExtendedRights “Ms-Exch-SMTP-Accept-Any-Recipient”
     
     

     Why Create a New Connector?
     
     Exchange prioritizes connectors based on specificity. For instance, if you have a SharePoint Server at 192.168.10.125, creating a relay connector exclusively for this IP (e.g., 192.168.10.125) ensures Exchange distinguishes between connectors. The Default Receive Connector allows connections from any IP, while the Relay Connector permits connections only from the specified IP. By explicitly setting the address on your Relay Connector, it takes precedence in serving SMTP connections from SharePoint, resolving the relay issue effectively.

      

      
      
     
     
     
     
     This cmdlet fetches the receive connector, adds a permission for Anonymous Logon in Active Directory, and assigns the Ms-Exch-SMTP-Accept-Any-Recipient permission for that group on the connector.