SOCKS4 Overview
SOCKS4 is the older version. It supports TCP connections only, does not support authentication, and cannot handle UDP traffic. It's simpler but more limited in functionality.
SOCKS5 Overview
SOCKS5 is the newer version. It supports both TCP and UDP, adds authentication support, allows IPv6 addresses, and can handle DNS resolution through the proxy. It's more versatile and secure.
Feature Comparison
SOCKS4: TCP only, no auth, IPv4 only, no DNS via proxy. SOCKS5: TCP + UDP, username/password auth, IPv6 support, DNS via proxy. SOCKS5 is strictly better in features.
When SOCKS4 Is Enough
SOCKS4 works for simple web browsing and basic applications that only use TCP. If you're using an older application that only supports SOCKS4, it's functional but limited.
Always Choose SOCKS5 When Available
SOCKS5 is the modern standard. It offers better security, more features, and broader compatibility. There's rarely a reason to choose SOCKS4 over SOCKS5 unless forced by legacy software.