The subnet mask 255.255.255.224 gives you 8 subnets with 32 available addresses. Each subnet must start with a subnet number and end with a broadcast number so technically that leaves you with 30 host addresses per subnet. This is still plenty if you only needed 20 per subnet. We have gone from one subnet with 255 addresses:

subnet mask wildcard 255 1111 1111 0 0000 0000 254 1111 1110 1 0000 0001 252 1111 1100 3 0000 0011 248 1111 1000 7 0000 0111 240 1111 0000 15 0000 1111 224 1110 0000 31 0001 1111 192 1100 0000 63 0011 1111 128 1000 0000 127 0111 1111 0 0000 0000 255 1111 1111 ip address classes a 0.0.0.0 – 127.255.255.255 b 128.0.0.0 – 191.255.255.255 IPv4 Network Class-B Subnet Cheat Sheet Private: 256 contiguos Class C, from 192.168.0.0/24 through 192.168.255.0/24 Subnet Mask Cheat Sheet - SHAKE A BABY IPv6 Subnet Cheat Sheet. IPv6 is a complete and different animal as far as subnetting goes. Please note the yellow rows as each has special common use or notes. If there is nothing in the "Amount of a /64" column that means it is to miniscule or to massive to justify calculation. Not much is the same with IPv6 compared to IPv4. IP Address Cheat Sheet - pbxbook.com

CIDR Prefix # of former class C nets

Private: 256 contiguos Class C, from 192.168.0.0/24 through 192.168.255.0/24 TCP/IP Cheat Sheet - DMC Cisco Networking Academy

IP Subnet Mask Cheat Sheet - Information - Information

IPv4 Subnet Mask Cheat Sheet Addresses Netmask Amount of a Class C /31 2 255.255.255.254 1/128 /30 4 255.255.255.252 1/64 /29 8 255.255.255.248 1/32 Jan 07, 2017 · Addresses Netmask Amount of a Class C /31 2 255.255.255.254 1/128 /30 4 255.255.255.252 1/64 /29 8 255.255.255.248 1/32 /28 16 255.255.255.240 1/16 /27 32 255.255.255.224 1/8 /26 64 255.255.255.192… Mar 11, 2019 · 2nd Subnet name and address range is : BackEnd_Subnet : 10.1.2.0/24. In the above two subnet each section of the subnet mask can contain a number from 0 to 256 . The number of IP can be vary as per the mask, as shown bellow. We can find more detail calculation on Subnet mask here. Subnet Mask Cheat Sheet