Q&A

Networking

Answers on IPs, VPNs, SOCKS, HTTP proxies, timeouts, encryption, and network behavior that affects scraping.

4 answers

All Anti-bot Basics BeautifulSoup Browser Automation Cloudflare CSS Selectors Data Extraction Headers and Cookies HTML Parsing HTTP Status Codes JavaScript Networking Python Rate Limits Selectors Selenium Web Scraping XPath

What does HTTP 499 mean and how do you fix it?

HTTP 499 is an Nginx code logged when the client closes the connection before the server responds. Fix it by aligning timeouts or speeding up the backend.

Apr 28, 2026

Are HTTP headers case-sensitive?

HTTP header names are case-insensitive per RFC 9110. Header values are case-sensitive unless the specific header's spec defines them as tokens.

Apr 28, 2026

What is HTTP error code 520, and how do you fix it?

Cloudflare error 520 means the origin returned an empty or unparseable response. Common causes are crashes, firewall blocks, and oversized response headers.

Apr 28, 2026

What is the HTTP 444 status code and what does it mean?

HTTP 444 is an Nginx-only code that closes the connection without sending any response. The client sees ERR_EMPTY_RESPONSE and the code appears in Nginx logs.

Apr 28, 2026