fsd

If you're dealing with Adobe Flash applets or AIR applications that access data via a Socket or XMLSocket object, you'll need to authorize the accessing applet or application to access the data. This is a security feature integrated by Adobe, and made mandatory with version 9.0.115.0. This is where fsd comes in- it is a Flash security daemon that a Linux machine can use to provide data for these applets and applications. The daemon is a very small, configurable server that offers this authorization.

In order to strengthen security, Adobe made it so that before version 7, it was possible to create a Flash applet that accessed data from foreign domains without proper authorization. This caused a lot of issues for companies that provide data like stock information, weather reports, etc. because everyone could access the data they provide. However, with Adobe Flash player version 7, a method was integrated to ensure that data cannot be accessed by unauthorized flash applets.

When you invoke a connection with an ActionScript Socket or XMLSocket object, the Flash Player automatically tries to connect to TCP port 843 on the server you configured the Socket or XMLSocket to, and sends a to this port. If this request is not answered correctly, or if this port is unreachable, a security sandbox violation is raised, and the connection to the service is not established.

If you want more information about these issues, you can find it on the Adobe Developer Center. As ZaKoTel started with developing Flash applets, we found it unsuitable that only Java-based data services were available to fulfill this task. As a result, we created a small configurable C server that can also be used on Java-free servers and is licensed under the terms of the GNU GPLv2.