Raw printing is what we define as the process of making a connection to port 9100/tcp of a network printer. It is the default method used by CUPS and the Windows printing architecture to communicate with network printers as it is considered as ‘_the simplest, fastest, and generally the most reliable network protocol used for printers_’. Raw port 9100 printing, also referred to as JetDirect, AppSocket or PDL-datastream actually **is not a printing protocol by itself**. Instead **all data sent is directly processed by the printing device**, just like a parallel connection over TCP. In contrast to LPD, IPP and SMB, this can send direct feedback to the client, including status and error messages. Such a **bidirectional channel** gives us direct **access** to **results** of **PJL**, **PostScript** or **PCL** commands. Therefore raw port 9100 printing – which is supported by almost any network printer – is used as the channel for security analysis with PRET and PFT. (From [here](http://hacking-printers.net/wiki/index.php/Port\_9100\_printing))
