ReadTheDocs - Spend your time on writing high quality documentation, not on the tools to make your documentation work.
SolarWinds Network Configuration Manager - SolarWinds is a leading provider of powerful and affordable IT infrastructure management software. Make IT look easy.
HackMD - Fast and flexible, real-time collaborative markdown, inspired by Hackpad.
Nmap - Nmap Free Security Scanner, Port Scanner, & Network Exploration Tool. Download open source software for Linux, Windows, UNIX, FreeBSD, etc.
Documize - Enterprise-grade wiki and knowledge management platform
Cisco Network Assistant - Cisco Network Assistant simplifies wired and wireless network management, and provides critical product information using Cisco Active Advisor.