Developer
localhost, ports in use, curl and tcpdump.
Learn 6
Tutorials 10
- Mac Network Commands: The Cheat Sheet
- curl -v: Debug HTTP Requests Step by Step
- curl Command: Examples for Every HTTP Task
- How to Edit the Hosts File on Mac
- lsof Command: Find Which Process Uses a Port or File
- nc (netcat) Command: Examples
- scp Command: Copy Files over SSH
- ssh Command: Connect, Keys and Tunnels
- tcpdump Command: Capture Packets on macOS
- wget Command (and How to Get It on Mac)
Fixes 44
- 502 Bad Gateway: What It Means and How to Fix It
- Port Already in Use on Mac: Find and Kill the Process
- "Connection Reset by Peer": Causes and Fixes
- "Permission Denied (publickey)": How to Fix SSH Keys
- "Self-Signed Certificate in Certificate Chain": How to Fix It
- "Socket Hang Up" in Node.js: Causes and Fixes
- "Unable to Get Local Issuer Certificate": Fixes for git, curl, npm and Python
- 304 Not Modified: What It Means
- 400 Bad Request: What It Means and How to Fix It
- 401 Unauthorized: What It Means (vs 403)
- 403 Forbidden: What It Means and How to Fix It
- 404 Not Found: What It Means and How to Fix It
- 405 Method Not Allowed: Causes and Fixes
- 410 Gone: What It Means (vs 404)
- 413 Request Entity Too Large: How to Fix It
- 415 Unsupported Media Type: How to Fix It
- 418 I'm a Teapot: The Joke Status Code
- 422 Unprocessable Entity: What It Means
- 429 Too Many Requests: What It Means
- 500 Internal Server Error: Causes and Fixes
- 503 Service Unavailable: Causes and Fixes
- 504 Gateway Timeout: How to Fix It
- Cloudflare Error 520: Unknown Error
- Cloudflare Error 521: Web Server Is Down
- Cloudflare Error 522: Connection Timed Out
- Cloudflare Error 524: A Timeout Occurred
- Cloudflare Error Codes: 520–526, 1015, 1020
- curl: (6) Could Not Resolve Host: How to Fix It
- ECONNREFUSED: Connection Refused in Node.js
- ERR_BLOCKED_BY_RESPONSE: What It Means
- ERR_CACHE_MISS: How to Fix It
- ERR_CLEARTEXT_NOT_PERMITTED (Android WebView): How to Fix It
- ERR_CONNECTION_REFUSED: What It Means and How to Fix It
- ERR_FAILED: How to Fix It
- ERR_HTTP_RESPONSE_CODE_FAILURE: What It Means
- ERR_TOO_MANY_REDIRECTS: How to Fix It
- ERR_UNKNOWN_URL_SCHEME: How to Fix It
- ERR_UNSAFE_PORT: Why Chrome Blocks Some Ports
- getaddrinfo ENOTFOUND: How to Fix It
- HTTP 499: Client Closed Request
- localhost Not Working on Mac (127.0.0.1 vs ::1)
- NSURLErrorDomain Errors on Mac and iPhone: What Each Code Means
- SSH "Connection Refused": How to Fix It
- SSH "Connection Timed Out": How to Fix It