The remote subnet is unknown to you, and doesn't affect your configuration in any way. You only need the IP address. Most likely, it is referring to the subnet of the networks in the encryption domain (i.e., the networks that pass through the VPN tunnel). You should know those. Or, it's referring to the subnet mask …
What is an Address Mask? (with pictures) Apr 20, 2020 What is an IP network mask? - Quora An IP network mask is a method of maximizing the number of IP addresses being used. It allows a group of addresses to be broken down into smaller, individual networks. Lets say I have an IP structure using the IP group 10.0.0.0. What is my IP | What is a Subnet mask? 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.
An IP address is divided into two parts: network and host parts. For example, an IP class A address consists of 8 bits identifying the network and 24 bits identifying the host. This is because the default subnet mask for a class A IP address is 8 bits long.
Subnet Mask Cheat Sheet - aelius.com
Subnet mask calculator With subnet mask you can split your network into subnets. Enter your IP address and play with the second netmask until the result matches your need. This type of notation is also known as CIDR. CIDR (Classless Inter-Domain Routing, sometimes known as supernetting) is a way to allocate and specify the Internet addresses
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. Mask (computing) - Wikipedia Masks are used with IP addresses in IP ACLs (Access Control Lists) to specify what should be permitted and denied. To configure IP addresses on interfaces, masks start with 255 and have the large values on the left side: for example, IP address 209.165.202.129 with a 255.255.255.224 mask.