Resources

Free network tools that run in your browser.

• CIDR Calculator — CIDR to IP Range
• Subnet Calculator
• CSR and Certificate Decoder

Networking concepts explained, with examples from a Mac.

• Common Network Ports: The Complete List
• HTTP Status and Error Codes: The Complete List
• Subnet Cheat Sheet (CIDR, Masks, Host Counts)

Commands and settings, step by step, tested on macOS.

• How to Flush the DNS Cache on Mac (Every macOS Version)
• Mac Network Commands: The Cheat Sheet
• Traceroute Command: How to Trace a Network Route

Network problems and error messages, and how to fix them.

• "Your Connection Is Not Private": What It Means and What to Do
• 502 Bad Gateway: What It Means and How to Fix It
• DNS_PROBE_FINISHED_NXDOMAIN: What It Means and How to Fix It

Honest comparisons with the apps you might use instead.

• Charles Proxy Alternative
• GlassWire for Mac? The Best Alternative
• Hands Off! Alternative for Mac

Head-to-head comparisons and roundups.

• The Best DNS Servers (Tested Live in Your Browser)
• Cloudflare DNS vs Google DNS (1.1.1.1 vs 8.8.8.8)
• Little Snitch vs Radio Silence

Processes, domains, ports, IPs and networks, looked up.

• 0.0.0.0: What It Means
• 1.1.1.1: Cloudflare's DNS Resolver
• 10.0.0.1: Router Login (Xfinity and Others)

Studies, launches and opinions.

• Apple Removed Network Utility: What to Use Now
• Introducing LightAtom
• Network Monitor vs Firewall: Which Do You Need?