For a subnet mask 192.16.1.8 , Please help me find out the default mask.?

Question

Please explain me how and also find the number of 1's that define the subnet.

Answer 1

the default is 255.255.0.0

the 1's com from comparing the ip address to the 255 etc

Answer 2

go to start, all programs, accessories, command prompt.

A black box will appear, type, ipconfig, press enter

you will see a line that say subnet mask if you follow it over that will be your default mask.

The number that you showed is a ip address used to find a computer on a network or on a local server.

Answer 3

192.16.1.8 Is an IP address (or possibly a subnet number), not a valid subnet mask.  It looks like this in binary:

11000000.00010000.00000001.0000100

Valid subnet masks look like this:

11111111.11111111.11110000.00000000 (255.255.240.0)

or this:

11111111.11111111.11111111.11000000 (255.255.255.192)

or this:

11111111.00000000.00000000.00000000 (255.0.0.0)

(please notice the fact that all of the ones are to the left and all of the zeroes are to the right)

Now, if 192.168.1.8 is the subnet number, and you need to find out the default mask, then we almost have enough info.

192.blah.blah.blah Is a class C address, so any subnet mask for it will look like this:

11111111.11111111.11111111.xxxxxxxx

255.255.255.X

Please note that the rest of this answer assumes you aren't using VLSM.  If you are, all bets are off.  If you don't know what VLSM is, you dont neet to worry about it.

Now, if all of the above x's are zeroes, then the address space is not segmented.  It is one large subnet, whose subnet number is 192.16.1.0 and whose broadcast address is 192.168.1.255

But if some of them aren't, then the address space will be split up.  If 192.168.1.8 is a subnet number, then you can be sure that each subnet contains either 2, 4, or 8 addresses.  

I know this because subnet numbers go up by powers of two.  you can go up by chunks of 2, 4, or 8 and get to 8

you can't go up by chunks of 16, or larger and get to 8, you'll miss it.

We can rule out two right away, that doesn't make any sense because one would be a subnet number and the other would be the broadcast address, so there is no room for usable addressing.  so it's either 4 or 8

If there are 4 addresses per subnet, the list looks like this:

subnet number -- range of valid addresses -- broadcast address

...

192.16.1.0 -- 192.16.1.1-192.16.1.2 -- 192.16.1.3

192.16.1.4 -- 192.16.1.5-192.16.1.6 -- 192.16.1.7

192.16.1.8 -- 192.16.1.9-192.16.1.10 -- 192.16.1.11

...

And as you can see, 192.16.1.8 lands on a subnet number.

However, 192.16.1.8 lands on a subnet number in one other case, and that is when there are 8 addresses per subnet.  the list goes like so:

...

192.16.1.0 -- 192.16.1.1 - 192.16.1.6 -- 192.16.1.7

192.16.1.8 -- 192.16.1.9 - 192.16.1.14 -- 192.16.1.15

...

Since 192.16.1.8  Happens to be the FIRST subnet number if we're counting by 8, and the second number if we're counting by 4, I'm betting your question wants us to be counting by eight

Now, to get the default mask.

since it is class C, we don't need to worry about the first three octets, they are 255.  The last octet, however, has got some number of 1's and some number of 0's

the number of 0's is given by

2^x=y

where y is the number of addresses per subnet and x is the number of 0's

so, in this case, there are 8 addresses, so there are 3 zero's

because 2^3=8

That means that our default subnet mask is

11111111.11111111.11111111.11111000

which is

255.255.255.248

(in case you were wondering, the number of 1's is given by 2^w=z where w is the number of ones and z is the number of subnets.  So here we have 32 subnets (256/8=32).  Since 2^5=32, there are 5 1's)

If we want the mask for the subnetting that has 4 addresses per subnet (just incase I guessed wrong about the intent of your question), we do the same thing:

2^x=4

x=2

2 zeros

2^w=64

w=6

6 ones

so our subnet mask is:

11111111.11111111.11111111.11111100

255.255.255.252

If you're interested in how to convert between 11111000 and 248, you can read about it in these two links:

http://www.wikihow.com/Convert-from-Bina...

http://www.wikihow.com/Convert-from-Deci...

Answer 4

An ip address needs a subnet mask, default mask is not used unless you have multiple routers and switches. If you put it on auto, it will be fixed.

A subnet mask should only have 255 and 1, so 192.16.1.8 is probably an ip adress.

If a subnet mask is 255.255.255.1, that means if the ip is 192.168.0.2, 192.168.0 identifies network, 2 identifies computer.

If subnet mask is 255.255.1.1 and ip is 192.168.0.2, 192.168 identifies network, 0.2 identifies computer.

Only change the subnet if you have over 255 computers on a network. Each computer must then be changed to use that subnet mask.