This article was previously published under Q259369
This article has been archived. It is offered "as is" and will no longer be updated.
ActiveSync 4.x requires the following Winsock Transmission Control Protocols (TCP) to be available:
5678 (Legacy Replication)
5679 (Handshake & Legacy Replication)
If socket port filtering occurs on any of these Winsock ports, ActiveSync does not synchronize with Microsoft Windows mobile devices.
Winsock ports can be filtered by firewalls and by some routers in a networked environment. They can also be installed locally on the desktop system running ActiveSync. Network administrators may filter Winsock ports as a security measure, to limit the types of connections that can be made to the server. If synchronization is being attempted on a network where the above ports are blocked, ActiveSync fails to synchronize with the connected Windows mobile devices.
In most situations, the Windows mobile device connects to the client. However, if ActiveSync synchronization does not begin, the connection eventually times out.
For more information, click the following article numbers to view the articles in the Microsoft Knowledge Base:
175523 Winsock TCP connection performance to unused ports
177699 How to use Windows NT Simple TCP/IP services for Winsock testing