From: gah@ugcs.caltech.edu   
      
   iamhereintheworld@gmail.com wrote:   
      
   > I just saw a video about this on youtube from elithecomputerguy ,   
   > but he leaves out all of the crucial details. I'm sure I CAN   
   > understand it, if I saw a video with animations and an in depth   
   > explanation. Can anyone point me to such a video?   
   > I really don't feel like *reading* about it, I just read the   
   > section on it in Andy Tanenbaum, but didn't get it.   
   > So, any videos out there?   
      
   The reason it is complicated at all is because it was added onto   
   the existing class A, B, and C addresses. With CIDR, some 20 years   
   now, that distinction is gone.   
      
   All you need to know is that IP (specifically IPv4) addresses are 32   
   bit numbers, and that the subnet mask separates the network part   
   from the host within network part.   
      
   Also, that IPv4 addresses are commonly written as four decimal   
   numbers, each representing an 8 bit value (between 0 and 255).   
      
   A reasonably popular network value is 192.168.1.x, where x is   
   the host within the network. The subnet mask 255.255.255.0   
   says that the 192.168.1 part is the network part, and the x   
   part is the host within network part.   
      
   Maybe more obvious if you write 255.255.255.0 in binary,   
   as 11111111111111111111111100000000.   
      
   (Note that the first and last address on the net are reserved   
   as broadcast addresses. As above, that would be x of 0 and 255.)   
      
   Most often, one doesn't want more than 254 hosts on a single ethernet   
   network, and so the 255.255.255.0 netmask is popular. Unless you   
   are short on addresses, there isn't much reason to go smaller.   
      
   -- glen   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)