• Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint
Share this Page URL
Help

Chapter 20. A Network Security Primer > Protecting a Network from Outside Attac...

Protecting a Network from Outside Attack

Another security risk for your network involves direct attack. Connecting your network to the Internet provides a nice wide conduit for folks who want to try to crack your network security and gain access to valuable network resources.

Direct network attacks can take different forms, and many of them are possible because of the way the TCP/IP protocol stack operates. Each protocol in the TCP/IP stack communicates on a particular channel, called a well-known port number (port numbers are discussed in Chapter 12, “TCP/IP Network Administration”). For example, HTTP operates on port 80, and FTP operates on port 21. There are, in fact, more than 1,000 well-known port numbers, and each of these ports is a potential path for an attack on your network. Firewalls provide a strategy for blocking these ports, and we will discuss firewalls later in the chapter.


PREVIEW

                                                                          

Not a subscriber?

Start A Free Trial


  
  • Creative Edge
  • Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint