| Platform SDK: DirectX |
Applications do not need to be rewritten to take advantage of the firewall support of DirectPlay. The default behavior is to use a dynamically allocated port from DirectPlay's range. This provides backward compatibility with existing applications, as well as the ability to use multiple DirectPlay applications on a single computer.
Additionally, applications can be written to take advantage of the new fixed-port feature of DirectPlay. You can choose a port number specifically for the application, and a firewall administrator need only open that particular port. See the section on selecting a specific port in the TCP/IP topic.
Users of DirectX 6.0 or later can still communicate with DirectX 5.0 users as long as no firewall is involved. This means that if even one computer is behind a firewall, peer-to-peer games with DirectX 5.0 computers will not work. Client/server games are allowed, as long as the host is DirectX 6.0 or later, and in each case where the line of communication between the host and a client will pass through a firewall, that client is DirectX 6.0 or later, as well.
Because of proxy architecture, you are limited to using a single computer. However, multiple applications (each using the dynamic DirectPlay range or unique application-defined ports) on the computer are still allowed.
For more information about using DirectPlay for firewall support, please see the following topics.