How do I figure out the subnet mask when given a ip address and no prefix?

I’m sure I missed something somewhere and I’ve been going thru my book trying to find it

My Boson labs often give me an ip address and tell me to assign it. In the solution, there will be thr accompanying subnet mask that you’re supposed to put with it. I know how yo subnet, I know about Network Bits, Subnet Bits, and Host Bits. I know the formula.

Like how does get you a subnet mask of

Hey John,

I assume that if you don’t have pre-defined subnet mask for your ip, then you should use the classfull method to assign the ip to a pool range.

If you know the proccess and requirement of the configuration for your network , you could also use your own subnets as required.

Hello John

When you are given an IP address to assign to a particular host or interface, the subnet mask should accompany that address so you can configure it appropriately. However, as @nitayp1 has correctly stated, if no subnet mask is provided, then in most cases it is assumed that you use the classful subnet mask.

The only way you would get such a subnet mask for this IP address is if it has been explicitly stated. If it has not been explicitly stated, and the mask is not classful, then I would have to conclude that a mistake has been made in the book or documentation you are reading.

I hope this has been helpful!