DKIM for Exchange Server and IIS SMTP Service
Add DomainKeys/DKIM signature to outgoing emails in Exchange Server or IIS SMTP service. Prevent the emails from your domain from being flagged as spam or junk mail by email servers which have Domainkeys/DKIM implemented (such as Hotmail, Yahoo mail and Gmail).
Windows 2000 or later (32bit/x64)
IIS SMTP Service or Exchange Server 2000/2003/2007/2010/2013/2016 installed