Answer
When troubleshooting mail flow problems between Microsoft Exchange servers and GFI servers, it may be required to enable the Microsoft Exchange Protocol Logging. Protocol logging records the Simple Mail Transfer Protocol (SMTP) conversations that occur between e-mail servers as part of message delivery.- Microsoft Exchange 2000 or 2003: How to enable SMTP protocol logging in Exchange 2000 Server and in Exchange Server 2003
- Microsoft Exchange 2007: How to Configure Protocol Logging
- Microsoft Exchange 2010: Configure Protocol Logging
- Microsoft Exchange 2013 and 2016: Configure Protocol Logging