How to calculate subnet mask knowing only ip?

Question

System administration

Hello! Please tell me how to calculate the subnet mask. There are many articles on the Internet, but there are no step-by-step instructions. Here is a network 10.20.1.0 and a host with the address 10.20.1.1. How to understand what the host's mask is? As I understand it, different address ranges have different masks. And how to calculate them, knowing only ip? Here is ip and you need to enter the mask. What will she be like? How to understand it? I read about bits and that you need to multiply something. Maybe there are articles in which the points sign how to do this?

Answer 1

The correct answer is using the network class . This network is class A, so its mask is 255.0.0.0. Unfortunately this answer is outdated as class networks have been out of use for a long time, and the actual answer is to ask the administrator in charge of the router closest to you, because. only he knows with what mask he configured addressing in your network segment. Any options from 255.255.255.252 to 255.255.255.0 are possible for the network address and IP you specified.

Answer 2

Раз
Два

Answer 3

Калькулятор.

Вот есть сеть 10.20.1.0 и хост с адресом 10.20.1.1.

В первом приближении 255.255.255.0.

Answer 4

Никак. Если бы это было возможно, то маску бы вообще не нужно было вводить.
Продайдеры могут тебе выделить IP и такую подсетку
255.255.255.0
а потом пожадничать/сэкономить и поменять маску на такую
255.255.255.252
при том, что IP-адрес останется тот же.

Answer 5

А есть таблица тогда какая-нибудь, где написано какому диапазону ip-адресов какую маску писать?