With this tool, your IIS SMTP Service and Exchange Server will be enabled to add DomainKeys/DKIM signature to outgoing emails from specified domain(s), which verify the DNS domain of an email sender and the message integrity, and in turn preventing 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). In the new version, it supports Exchange 2013 SP1 and signs DKIM on behalf of client domain. Requirements: Platform: Windows 2000 or later (32bit/x64) IIS SMTP Service or Exchange Server 2000/2003/2007/2010 installed Exchange 2007 requires SP1 rollup 9 or SP2 installed