WindowsAzureActiveDirectorySynchronization, also known as DirSync, synchronizes onpremises ActiveDirectoryobjects (users, contacts, and groups) with WindowsAzureActiveDirectory based services, such as Office 365. DirSync replicates all additions, deletions, and modifications of users, groups, and contacts from on-premises to Office 365. DirSync is designed to operate as a software-based set-and-forget “appliance”. For Office365, the purpose of DirSync is to enable coexistence between an onpremises ActiveDirectory/Exchangeenvironment and Office365 in the cloud system.