# What is this IP address?

I see an IP address = 10.0.0.0/24

my confusion is what is 0/24

Let me google that for youâ€¦

my confusion is 0/24 â€¦ this notationâ€¦what this means ? is it from 0,1,2,3â€¦upto 24 ? or what this means ?

I need help right at this spot.

betterâ€¦

I understand a network can be divided into multiple sub networks.
but the problem is with the notation. â€ś0/24â€ť . As a laymanâ€™s language can you please simplify this concept.

Please read this section, it is not very long. Both charts are explanatory.

checkedâ€¦too complicatedâ€¦could not understand much â€¦very difficult for a non-network guy

The /24 part tells you how many bits of the address are fixed in place.
The address consists of four numbers, each one being 8 bits. The total length of the address is 32 bits.

/24 says that the first three sets of numbers must remain fixed.

/26 says that the first three numbers and the first two bits of the fourth number must remain fixed. That leaves only 6 bits available to you, those being from 0 to 63. The highest and lowest values are automatically assigned (0 and 63), so you have 1 through to 62 that you can use.

If it were /30 then you would only have two bits to play with, for a total of 0 to 3. 0 and 3 are automatically assigned, leaving you with only 1 and 2 that you can use as hosts.

The main takeaway from this is that the /nn number says how many bits of the address must remain fixed. The remaining bits (excluding the top and bottom value) remain for you to use as you wish.

1 Like

Thanks Paul,

so the notation â€¦
10.0.0.0/24

means I can now play with these IP numbers : (// first 3 numbers kept fixed)
10.0.0.1,
10.0.0.2
10.0.0.3
â€¦
10.0.0.254

and 10.0.0.0 , 10.0.0.255 automatically assigned.

Is this correct ?

Yes. 0 and 255 would be unavailable. 1 through 254 would be yours to play with.

Back to an earlier link, the concept of network mask is shown here.

And if you have the time and interest, this Cisco intro for beginners is about as fundamental as anything Iâ€™ve seen.