Apple

• Apple Developer
• Apple Support
• Apple Support Communities
• Mac Research
• 9to5Mac

AI

• OpenAI
  • ChatGPT

Assembly

• i386
  • gcc x86 Assembly Quick Reference
  • Linux i386 Syscall Reference
  • Linux i386 System Calls
  • x86 Assembly Instructions
  • x86 Assembly Instructions - Wikipedia
  • X86 Opcode and Instruction Reference
  • x86 Registers
• x64
  • Linux x64 System Calls
  • x86_64 NASM Assembly Quick Reference

Bluetooth

• Bluetooth
• Bluetooth MAC Address Lookup

Books

• NoStarch

BusinessDev

• Federal
  • DoD SBIR/STTR
  • Grants.gov
  • NIST SBIR
  • US DOT SBIR
• Local
  • Carroll Technology Council
  • Howard Tech Council
  • Mid-Atlantic Gigabit Collaboratory, Inc - MAGIC
  • Maryland Tech Council
  • Technical.ly Baltimore

C/C++

• comp.lang.c - Infrequently Asked Questions
• C Code wiki
• Cprogramming.com
• C programming Interview questions and answers
• C - Tips on Programming
• c4learn.com
• fresh2refresh.com C tutorial
• GCC online documentation
• Learn-C.org
• Notes on C
• programiz.com C tutorial
• Programmers Heaven

Collaboration

• Jitsi Meet
• Rocket.Chat
• Skype
• Slack
• Teams
• Zoom

ConfigMgmt

• CVS - Concurrent Versions System
• CVS Opensource Development
• git
• Git for Subversion Users Cheat Sheet
• Subversion
• Subversion Commands and Scripts

DataAnalysis

• Elastic
• Grafana
• Kibana

Database

• Microsoft SQL Server
• MySQL
• Oracle Documentation
• PostgreSQL
• SQL Zoo
• SQLite

DataCenter

• Equinix
• Iron Mountain

DataFormats

• json

Debugging

• GNU gdb
• GNU gdb command cheat sheet

Documentation

• Confluence

DomainNames/IP Addresses

• AbuseIPDB
• American Registry for Internet Numbers (ARIN)
• dnstwist phishing domain scanner
• DNSWatch
• easyWhois
• GoDaddy
• Internet Assigned Numbers Authority (IANA)
• ICANN Domain Name Lookup
• InterNIC
• MXToolBox
• Network Solutions
• ultratools
• urlscan.io
• urlvoid
• viewDNS
• WhatIsMyIPAddress
• Whois - Domaintools
• Whois Lookup
• WintelGuy.com tools

ELF

• ELF - TheGeekStuff
• ELF - Wikipedia
• ELF Wiki - OSDev
• Systen V ABI

EMail

• Comcast mail
• Google mail
  • Takeout
• O365 mail
• proton mail
• Yahoo! mail
• Tools
  • Message Header Analyzer
  • Thunderbird

GeneralReference

• All Net Tools (insecure)
• ASCII Tables
• DNSstuff.com
• FAQ Archives
• FileFormat.info
• RapidTables

GovernmentNews

• ExecutiveGov
• Federal Computer Week
• FedScoop
• Government Computer News
• GovConWire
• Government Technology
• The Hill - Technology

Hardware

• HardwareHell
• Tom's Hardware

House

• Home Connectivity Blog

Humor

• Bullshit Bingo
• Dilbert
• xkcd

Kids

• Code Ninjas

Linux

• CentOS
• Debian Linux
• DistroWatch.com
• Fedora Project
• FreeBSD
• Gentoo Linux
• Kali Linux
• Knoppix Linux
• Linux Documentation Project
• Linux Kernel Archives
• Linux man pages
• LinuxQuestions.org
• Linux Today
• LWN.net
• NetBSD Project
• Packages Search
• Red Hat
• ROCK Linux (discontinued)
• Slackware Linux Project
• SUSE Linux
• ubuntu Linux
• SELinux
  • SELinux - Fedora
  • SELinux Wiki
  • SELinux - Wikipedia

Logs

• Logstash

MACAddresses

• adminsubnet MAC Address/Vendor Lookup
• coffer.com MAC Finder (insecure)
• MAC Address Lookup (insecure)
• MAC Vendor Lookup
• WintelGuy.com MAC/WWN lookup
• Wireshark OUI lookup tool

Microsoft

• Microsoft Community
• Microsoft Documentation
• Microsoft Documentation - Github
• Microsoft forums
• Microsoft Tech Community
• O365
  • Azure AD admin center
  • Exchange admin center (old)
  • Exchange admin center (new)
  • Microsoft 365 admin center
  • Microsoft 365 compliance center
  • Microsoft 365 security center
    • threat explorer
    • quarantine
  • Office 365 Security and Compliance Center
  • reddit Office365
• Sysinternals

Network

• Cloudflare Radar
• Netmask Quick Reference Chart (insecure)
• Shodan
• traceroute.org (insecure)
• Wireshark

News

• The Atlantic Tech News
• CIO.com
• CNET News
• Computer World
• Engadget
• eWEEK
• Fortune - Tech
• InformationWeek
• InternetNews
• ITworld
• ITworld Canada
• Kim Komando Technology
• Mashable Tech
• Motherboard - VICE
• Network World
• New Scientist - Technology
• PC Magazine
• The Register - UK
• SiliconANGLE
• Silicon Republic
• SiliconValley.com
• Slashdot Technology
• TechCrunch
• Techdirt
• Tech-FAQ
• Technology Review - MIT
• techradar.com
• techrepublic.com
• TechSpot
• Techworm
• TechXplore
• tom's guide
• Washington Post Technology
• Washington Technology
• Wired (limited free articles)
• ZDNet

Orgs

• ACM
  • ACM Digital Library
• AFCEA
  • AFCEA - Central MD Chapter
  • AFCEA - Washington DC Chapter
• Institute of Electrical and Electronics Engineers (IEEE)
• International Committee for IT Standards (INCITS)
• International Council on Systems Engineering
• International Organization for Standards (ISO)
• Internet Corporation for Assigned Names and Numbers (ICANN)
• Internet Engineering Task Force (IETF)
• Internet Society
• Project Management Institute
• USENIX Association
• World Wide Web Consortium (w3c)

Outages

• CurrentlyDown (insecure)
• Downdetector
• Is It Down Right Now?
• Is the Service Down?
• Outage.Report
• ServicesDown

Outreach

• Hour of Code

PortNumbers

• IANA Port Numbers
• SpeedGuide Ports
• Wikipedia List of TCP and UDP Port Numbers

Power

• APC
• CyberPower
• Eaton
• Tripp Lite

Programming

• CMake
• CodeProject
• Computer Science from the Bottom Up
• Experts Exchange (account required)
• GNU Make
• searchcode
• StackOverflow

ProjectTools

• Jira
• Trello

Python

• A Byte of Python
• programiz.com Python Tutorial
• LearnPython.org
• nixCraft Python
• Python
• Python Wiki
• Python Tutorial

RegExp

• regular-expressions.info
• Wikipedia Regular Expressions

Repository

• Bitbucket
• Dropbox
• GitHub
• Pastebin

Scripts

• Advanced Bash-Scripting Guide
• BASH Reference Manual
• commandlinefu.com
• Command Line Kung-Fu
• examplenow - Linux, UNIX command line examples

Shellcode

• Exploit Database
• Shellcoding for Linux and Windows Tutorial
• Shellcodes database for study cases

Software

• General sites
  • Awesome-Selfhosted Software
  • Awesome Sysadmin Software
  • CNET downloads
  • FileHippo.com
  • GNU Project - Free Software Foundation
  • MajorGeeks.com
  • Softpedia
  • tucows Downloads
• Tools
  • Atlassian
    • Atlassian Community
  • CCleaner
  • Notepad++
  • OpenOffice
    • OpenOffice Wiki

Speed

• Speedtest by Ookla
• Verizon Speed Test
• Xfinity Speed Test

Standards

• IEEE Standards

SysAdmin

• Admin's Choice
• reddit
  • sysadmin
  • talesfromtechsupport
• Server Fault

Training

• BrightTALK
• Career Academy
• Global Knowledge
• HOTT - Hands On Technology Transfer
• Intense School
• Khan Academy
• Learning Tree International
• MIT OpenCourseware
• Open System Resources - OSR
• Technology Training Corporation
• TrainACE
• TainingCamp
• TrainUp.com
• UMBC Training Center

Unix

• Beej's Guide to Unix Interprocess Communication
• The Geek Diary
• ITtoolbox - UNIX
• unixadminschool
• UnixArena
• UNIXGuide.net
• Unix Guru Universe
• Unixwiz.net
• Wiki-UX.info

URLShorteners

• bitly
• Google URL Shortener (discontinued)
• tinyurl

Virtualization

• boxcutter
• Vagrant
• VirtualBox
• VMware

Web

• Bravenet
• BuiltWith
• Dreamhost
• WordPress
• Browsers
  • Brave
  • Chrome
  • Edge
  • Firefox
  • Opera

Wireless

• Cellular Telecommunications Industry Association (CTIA)
• WiGLE - Wireless Network Mapping