Reference

Dense, scannable lookup pages for commands, codes and syntax.

• CIDR and Subnet Mask Cheat Sheet
• Common Network Ports Cheat Sheet
• Git Cheat Sheet
• HTTP Status Codes Cheat Sheet
• Linux Command Line Cheat Sheet
• Regular Expressions (Regex) Cheat Sheet

Plain-language explanations of how the things behind our tools work.

• How Compound Interest Works
• How DNS Works
• How Email Authentication Works: SPF, DKIM and DMARC
• How Hashing Works
• How HTTPS and TLS Work
• How Subnetting Works

Step-by-step walkthroughs for everyday tasks, each with the tool that does the job.

• How to Check DNS Propagation
• How to Check If an Email Is Spoofed
• How to Choose a Subnet Mask
• How to Compare Loan Offers
• How to Find Where a Photo Was Taken
• How to Verify a File Checksum

Side-by-side comparisons that explain the difference and when to choose each option.

• 15-Year vs 30-Year Mortgage
• IPv4 vs IPv6
• JSON vs YAML vs XML
• MD5 vs SHA-256 vs bcrypt
• Symmetric vs Asymmetric Encryption
• TCP vs UDP

Short definitions of technology, security and finance terms.

• APR
• BMI (body mass index)
• DNS
• Hash
• IP address
• JWT