SOCKS (Socket Secure) is a protocol that routes network packets between a client and a server through a proxy server. It is often used for anonymity and bypassing network restrictions. There are two main versions of the SOCKS protocol: SOCKS4 and SOCKS5. While both versions serve the same basic purpose, there are some key differences between the two.

One of the main differences between SOCKS4 and SOCKS5 is their level of authentication and security. SOCKS4 only supports a simple username/password authentication, while SOCKS5 offers more advanced methods such as GSS-API (Generic Security Services Application Program Interface) and challenge-response authentication. This makes SOCKS5 more secure and less susceptible to unauthorized access.

Another important distinction is the support for various networking protocols. SOCKS4 only supports TCP (Transmission Control Protocol) connections, which means it cannot handle UDP (User Datagram Protocol) and ICMP (Internet Control Message Protocol) traffic. On the other hand, SOCKS5 supports both TCP and UDP, making it more versatile and suitable for a wider range of applications.

Furthermore, SOCKS5 introduces the concept of address resolution. This means that SOCKS5 can resolve domain names on behalf of the client, whereas SOCKS4 requires the client to resolve the domain names before initiating the connection. This feature simplifies the configuration process for clients using SOCKS5.

Additionally, SOCKS5 includes support for IPv6, the latest version of the Internet Protocol, which provides a larger address space and more efficient routing. This ensures that SOCKS5 is compatible with the latest networking technologies and can accommodate future advancements in internet infrastructure.

In summary, while both SOCKS4 and SOCKS5 serve as proxy protocols for routing network traffic through a proxy server, SOCKS5 offers enhanced security, support for a wider range of networking protocols, address resolution capabilities, and compatibility with IPv6. These improvements make SOCKS5 a more robust and versatile protocol compared to its predecessor, SOCKS4. As a result, many modern applications and services prefer to use SOCKS5 for their proxy needs.