Hello, John. If you break the address and the subnet mask down into binary, it may make a little more sense. The 0-255's make it easier for us humans to understand. The equipment only sees a long string of 0's and 1's. That 255 only makes a difference when using a classful mask.
Here is how it breaks down: 00011000.00001111.01111101.11111111 (Address) 11111111.11111111.11111000.00000000 (Mask) I included the decimal points to aid readability. If you follow the bits, you'll see the broadcast address for this segment is 24.15.127.255. That is equal to all the host bits being set to 1's (all 11 of them). The subnet address for this segment is 24.15.120.0. The 0 address you are concerned about is 24.15.120.0. The 255 address is 24.15.127.255. This subnet has 2048 total addresses, 2046 valid addresses. When you work with CIDR (Classless Inter Domain Routing), this makes much more sense. It seems everyone starts learning TCP/IP addressing with classful addresses, which adds to the confusion. Classful works for most networks but sometimes can hurt the learning process later on. The key to remember here: BINARY. Don't forget: BINARY Did I mention BINARY?? I harp on that because I have tried teaching many engineers how to subnet only for them to keep asking the same question you did. Hope this helps. Ken >>> "John Green" 10/26/01 08:22AM >>> the IP address alloted by the dhcp server to my home computer (via cable ie cable modem connection) is IP address 24.15.125.255 subnet mask 255.255.248.0 def gw 24.15.125.1 ok look ar the last quad .... it is 255 !!! i can't believe this. do you how this is possible ? 0 and 255 are rserved for network and broadcast addresses..... please email me asap........... __________________________________________________ Do You Yahoo!? Make a great connection at Yahoo! Personals. http://personals.yahoo.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=24253&t=24238 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
