Introduction to Disclaimer, S/MIME for IIS SMTP Service and Exchange Server
With this tool, your IIS SMTP Service and Exchange Server will be enabled to add disclaimer and digital signature to outgoing emails from specified sender(s) or domain(s). Moreover, email encryption (with using the recipient's digital certificate) and S/MIME (Secure / Multipurpose Internet Mail Extensions) will become fully supported in your Exchange server.
See Also
Using Disclaimer, S/MIME Sink
Email Disclaimer
ADSI Variables in Disclaimer
Digital Signature
Email Encryption
Appendix - Set up DomainKeys/DKIM
Appendix - Set up SPF record in DNS server