Conventions

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning. Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "The message is OFPT_BARRIER_REQUEST and has no message body. " A block of code is set as follows:

if packet.dst not in self.macToPort: 
          log.debug("Port for %s unknown -- flooding" % 
          (packet.dst,)) 
            flood() 
        else: 
        port = self.macToPort[packet.dst] 

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

if packet.dst not in self.macToPort: 
          log.debug("Port for %s unknown -- flooding" % 
          (packet.dst,)) 
            flood() 
        else: 
        port = self.macToPort[packet.dst]  

Any command-line input or output is written as follows:

git clone https://github.com/noxrepo/nox

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "Configure the VirtualBox for the Host-Only Network Details from File | Preferences | Networks | Host-only Networks | DHCP Server."