2014年11月19日 · Today's Class C with a subnet mask of 255.255.0.0 equals Class B. This is because the subnet is the only remnant of the old Class system, a concept that only exists today in routing tables for quantifying the number of IP addresses in an IP address segment.

2017年1月23日 · i have the following class B : 172.16.0.0 /16 . as in the image : i want someone to confirm that the solution is correct for the first 3 sub-networks : we will take 4 bits to have 16 networks that can fit the request , so my new subnet mask is : 255.255.240 .0. now , the first three networks are (the magic number is 16 ):

(Quick note, even if you probably know it: class B addresses use the first 16 bits for the network id, and the remaining 16 bits are available for machines). The mask 255.255.0.0 allows only for one network, all ips from the Class B. If you want to have subnetworks, at least one bit from the machine part of the ip will have to be used for it.

2015年12月8日 · One could say that 255.0.0.0 is implied for class A, and is the "network mask". Likewise, 255.255.0.0 would be the "network mask" for class B. Then, if you wanted to have additional bits to identify subnets within a class B network, a person could use up 10 additional bits for subnets within that network.

2015年3月25日 · How you do know this: look at a VLSM subnetting chart that shows the /24 through /30 IPv4 subnet sizes. You'll find that /25 has two subnets. The /24 subnet mask is 255.255.255.0, the /25 subnet mask is 255.255.255.128 (which is 128 more than the /24), the /26 subnet mask is 255.255.255.192 (which is 64 more than the /25).

2021年6月7日 · The default subnet masks are three subnet masks that correspond to the standard Class A, B, and C address assignments. Class Binary Dotted-Decimal Network Prefix A 11111111 00000000 00000000 00000000 255.0.0.0 /8 B 11111111 11111111 00000000 00000000 255.255.0.0 /16 C 11111111 11111111 11111111 00000000 255.255.255.0 /24

the first binary digits = 0 for class a, 10 for class b, 110 for class c, 1110 for class d and 1111 for class e (experimental). you have class b. which default subnet is 255.255.0.0. So to determine you should convert intp network info use the 2'n-2=y formula.

2012年2月27日 · A subnet mask is used to do a bit wise operations on an IP address, in conjunction with a network address. If my memory serves me well, you take an IP address and do a bit wise AND on it and the subnet mask for a given network. If the result equals the network address, then the IP address is on that particular network.

2014年2月10日 · In this case, a 10.0.0.0 is a Class A network, or a /8 CIDR block. Therefore, this network consists of 8 bits with a mask of 255.0.0.0. Subnetting a network means borrowing bits, and the subnet mask (think of it as the extended mask) tells you how many bits have been borrowed. In this case, a 255.255.240.0 means the 255.240 is the "extended" part.

2014年2月10日 · I have a class 'B' IP address 172.16.XXX.XXX in my machine. But from Wikipedia I get that class 'B' should have 255.255.0.0 as subnet mask. The "class B" IANA-reserved private network actually has subnet mask 255.240.0.0, not 255.255.0.0. Let me offer some clairity on how subnet masks work. IP addresses enable: