What Is an Anonymous Proxy?

The term is used in two ways, and it helps to know which one a page means.

Both meanings share the limit in the second quote: the proxy hides your IP from the website, never from the proxy itself.

An anonymous proxy works like any forward proxy, plus one edit to the request:

1. Your browser or script sends the request to the proxy's address and port.
2. The proxy opens its own connection to the website, so the site's server records the proxy's IP as the visitor.
3. For a plain-HTTP request, the proxy rewrites the headers on the way: it removes your IP, or replaces it with a placeholder, and adds a Via header that names the proxy.
4. The website answers the proxy, which passes the answer back to you.

A plain-HTTP request leaving an anonymous proxy can look like this. The proxy's IP is the connection address the server sees; your IP appears nowhere:

GET http://example.com/ HTTP/1.1
Host: example.com
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64)
Via: 1.1 proxy.example.net (squid)
X-Forwarded-For: unknown

That is roughly what the open-source Squid proxy sends with its via setting on (the default) and forwarded_for off, which, per Squid's documentation, makes the header read X-Forwarded-For: unknown instead of your address (Squid: forwarded_for; Squid: via; both directives exist up to Squid v7). MDN describes Via as a header "added by proxies, both forward and reverse" (MDN: Via).

Over HTTPS, the level stops mattering. For an HTTPS site, your browser asks the proxy to open a tunnel with the CONNECT method, and the proxy relays encrypted bytes it cannot read or edit (MDN: Proxy servers and tunneling). A tunneling proxy cannot add a Via or X-Forwarded-For header to a request it can't see, so on HTTPS pages a transparent, anonymous or elite proxy all look the same at the header level. What still differs is the IP itself.

So an anonymous proxy is an IP mask. It is useful for that, and it is not anonymity in the sense of nobody knowing who you are.

• WebRTC. Browsers use STUN servers to discover the device's public address for calls (MDN: WebRTC protocols); a page can trigger that and learn your real IP if the browser doesn't route WebRTC through the proxy.
• DNS. With some setups, the browser resolves host names through your own DNS resolver, which shows your network which sites you visit.
• Apps that ignore the setting. A system proxy setting is used only by the apps that honor it.

Free anonymous proxies add risks of their own. You don't know who runs them; an operator can read and change any unencrypted traffic and log everything. That is covered in are free proxies safe.

There is also a "distorting" variant that puts a made-up IP in X-Forwarded-For. The full comparison, with how to test each level, is in elite, anonymous and transparent proxies. A proxy that also tries to hide that it is a proxy is often sold as "hidden" or "incognito"; see hidden proxy servers.

The header level and the IP type are separate questions. A residential proxy gives the website an IP from a home internet provider instead of yours, so your IP is hidden; whether the provider adds proxy headers to plain-HTTP requests is a matter of its setup, and over HTTPS no headers can be added at all.

For ProxyField: you connect to gate.proxyfield.io:7000 over HTTP, HTTPS or SOCKS5, and each request leaves through a residential IP from the pool of 412M+. The ProxyField gateway adds no Via, X-Forwarded-For or Forwarded header and removes Proxy-Authorization before the request goes to the site. Like every provider, ProxyField knows which account sent the traffic, and it acts on abuse reports under its acceptable use policy.

What a residential IP changes is how the site classifies you: as a visitor on a consumer ISP rather than on a datacenter or a known proxy list. More on that in what a proxy IP address is.

• Keeping your IP from the sites you visit, for example when you research competitors and don't want your office IP in their logs.
• Seeing a site from another location, such as local prices, search results or ads.
• Collecting public data, where the point is not to send every request from one address. Here the IP type and rotation matter more than the anonymity level: a scraper over HTTPS never shows proxy headers anyway.

What they are not for: anything the site or the law forbids. Hiding your IP doesn't change what you are allowed to do; see are proxies legal.

1. Enter the proxy in the app that should use it: the browser or system proxy settings, or the proxy option of your script. The fields are host, port, and a username and password or an allowlisted IP. Where the settings live on each system is in proxy settings.

2. Check the IP the site sees. With ProxyField, for example:

   ShellCopy Shell code

   curl -x gate.proxyfield.io:7000 -U "<login>-country-us-city-new_york:<password>" https://api.ipify.org

   The answer should be a US residential IP, not yours.

3. Check the headers. Request a page that echoes request headers over plain HTTP and look for Via, X-Forwarded-For and Forwarded. The elite proxy guide has a short header echo you can run on your own server.

4. Check for leaks with the proxy on: a WebRTC test and a DNS leak test in the same browser. Our proxy checker covers the IP, location and type.

Need other IPs for research or data collection? ProxyField residential proxies: 412M+ IPs in 195+ countries, city targeting, HTTP, HTTPS and SOCKS5, from $1.95/GB. Start with the Easy Trial: 1 GB for $2.95.