WindowsAzureActiveDirectorySynchronization, also known as DirSync, synchronizes onpremises ActiveDirectoryobjects (users, contacts, and groups) with WindowsAzureActiveDirectory based services, such as Office365. DirSync replicates all additions, deletions, and modifications of users, groups, and contacts from onpremises to Office365. 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.