If testing these proxies, use a sandboxed environment or a dedicated VPN to prevent exposing your local network to potentially malicious endpoints.
If the goal is secure browsing, transition from SOCKS4 to SOCKS5 or a HTTPS-based proxy to ensure better compatibility and security features. 3313 socks4.txt
Because SOCKS4 lacks encryption and authentication, traffic passed through these proxies is visible to the proxy operators. There is a high risk of Man-in-the-Middle (MitM) attacks or data logging by unknown entities. If testing these proxies, use a sandboxed environment