As has been said there is no way to determine your sub-net mask from the internet. Well at some point the powers that be will have assigned your ISP a block of IP address, but this may be entire clas B network, they will the have subnetted this and decided what parts of it they will assign to there clients (ie you) what they will use for web hosting and other services ect and what will be

What is my IP address? The Internet Protocol Address (or IP Address) is a unique address that computing devices such as personal computers, tablets, and smartphones use to identify itself and communicate with other devices in the IP network.Any device connected to the IP network must have a unique IP address within the network. An IP address is analogous to a street address or telephone number in that it is used to what does 192.168.0.1/32 mean? - Ars Technica OpenForum Dec 04, 2002

what does 192.168.0.1/32 mean? - Ars Technica OpenForum

Guide to Subnet Mask (Subnetting) & IP Subnet Calculator

A subnet mask divides the IP address into the network address— ‘masking’ or hiding it — and host address. The host part then can be divided into a subnetwork (or a subnet), and host address, in case there is a need for additional subnetwork to boost performance and security of the network.

What is a Subnet Mask Address and How to Find Yours The job of a subnet mask is to hide the network element of an IP address. Only the host element is visible. We will explain what a Class C IP address is in more detail later, but one of the most common Class C subnet masks is 255.255.255.0. Like an IP address, each section of the subnet mask address can contain any numbers from 0 to 255. IP Tutorial: Subnet Mask and Subnetting Subnet Mask. Perhaps the most recognizable aspect of subnetting is the subnet mask. Like IP …