for IPv4, the size of the local net is 2 to the power of 32 net the CIDR (network portion) or for 192.168.0.0/24 the local net is 2 to the power of (32-24) or 2^8 or 256 - starting at 192.168.0.0 and ending with 192.168.0.255 for IPv6 the network and local sizes are set at 32 each so in the distant future you won't have to worry about this..
nice class breakout - Kevin & Kenn - thx On Mon, Aug 31, 2015 at 2:55 AM, <[email protected]> wrote: > Hi Keith, > > If I recall correctly, the /24 part of 192.168.0.0/24 is the subnet specified > in CIDR notation (Classless Inter Domain Routing). > > Think in binary terms, that /24 equals 11111111.11111111.11111111.00000000 > (note there's 24 1's) equals 255.255.255.0 so is a class C subnet with the > first three octets being the network mask. > > Likewise if you had an IP addy followed by a /8 that equals > 11111111.00000000.00000000.00000000 equals 255.0.0.0 so is a class A subnet. > > Called octets cuz there's 8 bits hence a decimal max of 255. > > CIDR is usually seen at ISP's or in enterprise networks that need to subnet > further as the network mask does not have to align with the octet boundary as > it does in the classfull network addressing we're used to. That's where > things get weird and all this because those silly routers only speak binary. > :] > > If you're seeing 192.168.0.0/24 in a zenmap target field it means scan > everything from and including 192.168.0.0 to 192.168.0.255. > > > IP network classes or Classfull Network Addressing > > - Range - - mask - > # of networks # of nodes CIDR mask > A 1.1.1.1 - 126.255.255.255 255.0.0.0 126 > 16,777,214 /8 > B 128.0.0.1 - 191.255.255.255 255.255.0.0 > 16,384 65,534 /16 > C 192.0.0.1 - 223.255.255.255 255.255.255.0 2,097,151 > 254 /24 > D 224.0.0.1 - 239.255.255.255 > E 240.0.0.1 - 255.255.255.255 > > > > --Kenn > > --------------------------------------------------- > PLUG-discuss mailing list - [email protected] > To subscribe, unsubscribe, or to change your mail settings: > http://lists.phxlinux.org/mailman/listinfo/plug-discuss --------------------------------------------------- PLUG-discuss mailing list - [email protected] To subscribe, unsubscribe, or to change your mail settings: http://lists.phxlinux.org/mailman/listinfo/plug-discuss
