# What is Subnetting? **URL:** \ **Category:** Lessons Discussion\ **Created:** [January 10, 2017, 8:52am UTC](https://forum.networklessons.com/t/what-is-subnetting/1395 "2017-01-10T08:52:22Z")\ **Posts on this page:** 1\ **Showing post:** 5
**Author:** ![lagapidis](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/lagapidis/32/4949_2.png) [@lagapidis](https://forum.networklessons.com/u/lagapidis)\ **Post date:** [May 6, 2019, 4:38am UTC](https://forum.networklessons.com/t/what-is-subnetting/1395/5 "2019-05-06T04:38:40Z")
Hello Rick > [@packetflow](#): > > When subnetting a block into small subnets do you calculate from the classful subnet mask or the prefix. It all depends on what the requirements are. Remember that subnetting is something that you end up applying to a real world network so the network range you start off with can be anything. If you are given a network of 192.168.0.0/23 and you are asked to further subnet it to segments of /26 then that is what you will do. There is no rule that says you must start with a /16 or /24. Now if you are told to specifically come up with classful result, then this means that the resulting subnets must be classful. So if you are originally given the 192.168.0.0/23 range then the resulting subnets you create must have a /24 subnet mask. I hope this has been helpful! Laz --- _[View the full topic](https://forum.networklessons.com/t/what-is-subnetting/1395)._