LightAtom

What Is a Proxy Server?

A proxy server forwards your requests to websites and returns the answers, so the site sees the proxy instead of you. It's narrower and simpler than a VPN.

A proxy server is an intermediary that makes network requests on your behalf: your app connects to the proxy, and the proxy connects to the website. Sites see the proxy's IP. Unlike a VPN, a proxy usually handles only the apps or protocols configured to use it, and doesn't necessarily encrypt anything.

How it works

The browser sends a request to a proxy server, which forwards it to the website; the website sees the proxy's IP.

Types of proxy

  • HTTP/HTTPS proxy: handles web traffic. For HTTPS, the browser sends CONNECT host:443 and the proxy relays the encrypted stream without reading it.
  • SOCKS5 proxy: relays any TCP (and UDP) connection; used by SSH tunnels (ssh -D) and Tor.
  • Transparent proxy: intercepts traffic without any configuration on your device, as on some company and school networks.
  • Reverse proxy: sits in front of servers rather than clients; a different job altogether.

Common uses

Company filtering and caching, reaching a network through a jump host, scraping from different IPs, and debugging tools like Charles or Proxyman that inspect your own app's traffic.

Proxy vs VPN

A VPN captures all traffic at the operating-system level and encrypts it to the server. A proxy covers only what's pointed at it, and plain HTTP or SOCKS proxies don't encrypt the hop to the proxy.

Side by side

ProxyVPN
CoversConfigured apps or protocolsAll traffic
Encrypts to serverNot necessarilyYes
Set up inApp or system proxy settingsVPN app or system VPN
Hides your IPFrom sites using itFrom all sites
Typical useFiltering, debugging, scrapingPrivacy, remote access

Examples

  • ssh -D 1080 user@server creates a SOCKS proxy on your Mac; set a browser to use localhost:1080 and its traffic exits from the server.
  • curl -x http://proxy.example.com:8080 https://example.com sends one request through a proxy.

On a Mac

System Settings › Network › Wi-Fi › Details › Proxies sets system-wide proxies; Safari and most apps follow them. scutil --proxy prints the current settings. An unexpected proxy here is worth investigating: adware sometimes sets one.

See it in the app

LightAtom's connections view shows when apps connect to a proxy instead of directly to sites, and which apps ignore it.

Frequently asked questions

What is a proxy server used for?

Forwarding requests on behalf of clients: filtering, caching, hiding client IPs, reaching restricted networks and debugging traffic.

Is a proxy the same as a VPN?

No. A proxy relays traffic for apps that use it; a VPN tunnels and encrypts all of the device's traffic.

How do I check proxy settings on a Mac?

System Settings › Network › your connection › Details › Proxies, or run scutil --proxy in Terminal.

Are free proxies safe?

Often not. The operator can log and, for plain HTTP, modify your traffic. Use only proxies you trust.

LightAtom team

The people who build LightAtom, a network monitor for macOS.