> read anything (public folder) from my server as I have not installed > ADC. So, how can Exchange 2000 connector communicate with my 5.5 > connector (without ADC installed)?? You do not have to install the ADC on both sides. They must have installed the ADC on their side at the time of the upgrade. > We r supposed to be in the same organization (JAPAN) > which is housed in TOKYO HQ but different sites based on overseas > branches (TOKYO, SINGAPORE, HONG KONG...) That would work just fine with an ADC configured on their end. They are having trouble accessing public folders housed on your server? I assume that the folders were replicated between the sites prior to their upgrade? There are essentially three different kinds of ADC's that can be installed on a server with the ADC application on it: 1) Configuration connector - this is automatically installed on an upgraded server and replicates the Exchange 5.5 directory between Exchange 5.5 and 2000. This connector has a name ending in _CA. 2) A connector that establishes the link between Active Directory and the SRS (the SRS is Exchange 2000's emulated 5.5 server). There are always two of these connectors. One between the SRS and Active Directory and a second one between the SRS and the other Exchange 5.5 site. 3) A public folder connector for replicating public folders between the Exchange 5.5 and 2000 servers. I wonder if they installed the public folder connector? I do have public folder replication between Exchange 2000 and another Exchange 5.5 site (in the same organization) so I know that it works when properly configured.