What is a SOCKS4 proxy?

A SOCKS4 proxy is an older proxy protocol that forwards TCP traffic between your application and a destination server. The destination sees the proxy’s IP, not your device’s IP.

TL;DR: SOCKS4 is a TCP‑only proxy from the 1990s. It has no modern authentication and is mostly obsolete, but still appears in some legacy systems.

How SOCKS4 works (simple)

When you configure an application to use a SOCKS4 proxy, the flow is straightforward:

  1. Your client connects to the proxy (e.g. proxy.example.com:1080).
  2. Your client sends the destination IP address and port to the proxy (no DNS hostname here).
  3. The proxy opens a TCP connection to that destination.
  4. The proxy then forwards data back and forth between your app and the server.

Diverted traffic is only TCP: no UDP support, which limits its usefulness for modern apps that need voice, gaming, or other UDP‑based protocols.

Important: SOCKS4 does not encrypt traffic by itself, and it has no built‑in authentication. Anyone who can reach the proxy can often use it as an open relay if not firewalled.

What SOCKS4 is good for

  • Legacy applications that only understand SOCKS4 (some older tools, internal scripts).
  • Simple TCP tunneling where you just need to change your IP without advanced features.

In practice, SOCKS4 is largely outdated. Modern tools prefer SOCKS5 because it adds UDP support, authentication, and cleaner DNS semantics.

SOCKS4 vs SOCKS5

  • SOCKS4
  • TCP only.
  • No authentication built into the protocol.
  • No support for DNS hostnames (you must pass an IP).

  • Simple, lightweight, mostly historical.

  • SOCKS5

  • TCP + UDP.
  • Multiple authentication options (none, username/password, GSS‑API).
  • Can relay DNS resolution through the proxy itself.
  • Better fit for modern apps, gaming, and voice tools.

If your client and proxy both support SOCKS5, choose SOCKS5 over SOCKS4.

Safety notes (read this)

  • SOCKS4 does not encrypt your traffic; it only masks your IP.
  • Open, unauthenticated SOCKS4 proxies are easy to abuse and often unreliable.
  • Prefer authenticated proxies you control or trust, and use end‑to‑end encryption (HTTPS/TLS/VPN) when confidentiality matters.