You can monitor the security of replication and remote data access (RDA) in Microsoft SQL Server Compact 3.5 by using the security auditing mechanisms built into Microsoft Windows and Microsoft Internet Information Services (IIS). Auditing consists of creating auditing polices regarding access to your IIS Web server and NTFS file system directories and files, and monitoring the security logs to detect any access attempts by unauthorized persons.
For more information, see the IIS documentation.