Proxy servers explained: types, uses and limits

A proxy server is a machine that makes network requests on your behalf. The website you visit sees the proxy’s IP address instead of yours. Everything else about the request depends on the type of proxy and how it is configured.

Types by protocol

• HTTP: fetches web pages for you and can read and change them.
• HTTPS (CONNECT): opens a tunnel so TLS runs between you and the site.
• SOCKS4 and SOCKS5: relay any TCP connection; SOCKS5 also UDP.

The protocol comparison covers these in detail.

Types by where the IP comes from

• Datacenter: servers in hosting networks. Fast and cheap, and easy for websites to recognise.
• Residential: home connections. Harder to block, usually sold by commercial providers.
• Mobile: phone network addresses shared by many users.

Anonymity levels

A transparent proxy passes your real IP on in a header, an anonymous one hides your IP but says it is a proxy, and an elite proxy does neither. You can see which one you have with a proxy judge.

Free public proxies

The addresses in public lists, including ours, are servers that accept connections from anyone. Some are run on purpose, many are misconfigured machines. They are useful for testing, research and scraping where failures are acceptable. They are a bad idea for anything private: the operator can log or alter unencrypted traffic, and a large share of them stops working within hours.

Practical rules: only send traffic you would not mind someone reading, prefer https:// targets, check proxies before use, and rotate through many rather than trusting one.

Common uses

• Checking how a site looks from another country.
• Spreading automated requests across many IPs.
• Testing your own firewall, rate limits or geo-blocking.
• Research on the open proxy ecosystem; see the archive.