ipcalc - IP Calculator. ipcalc takes an IP address and netmask and calculates the resulting broadcast, network, Cisco wildcard mask, and host range. By giving a second netmask, you can design subnets and supernets....
Efficient IP DNS Security - Efficient IP DNS Security is a 360 degree DNS security and network protection solution that fills the DNS security gap left by traditional security systems.
LanCalculator - LanCalculator - IP Subnet Calculator for IPv4/IPv6 Networks - LizardSystems
Cloudflare DNS - Install the free app that makes your phone’s Internet more fast, private, and reliable.
whatmask - Whatmask is a small C program that will help you with network settings and subnet calculations.
Cisco Umbrella DNS-layer security - Cisco Umbrella DNS-layer security is a leading provider of network and recursive DNS services that provide the quickest and most effective way to improve your security stack.