Dan York on Twitter: "Nice cheat sheet for #IPv4 subnetting (and a good reminder that if you move to #IPv6 you don't have to worry as much about all these smaller subnets
Useful subnetting cheat sheet. This will help when subnetting. ┃ Securitron Linux blog.
Subnetting Cheat Sheet Download Printable PDF | Templateroller
CIDR Subnet Mask Cheat Sheet | NetworkProGuide
Networking Part III: Networking 101 ~ Crystal Tenn