When initiating updates, OfficeScan clients first get updates from the update source specified on the Updates → Networked Computers → Update Source screen. If the update is unsuccessful, the clients attempt to update from the OfficeScan server. Selecting this option enables clients to attempt to update from the Trend Micro ActiveUpdate server if the update from the OfficeScan server is unsuccessful.

A pure IPv6 client cannot update directly from the Trend Micro ActiveUpdate Server. A dual-stack proxy server that can convert IP addresses, such as DeleGate, is required to allow the clients to connect to the ActiveUpdate server.