Proxy Server SOCKS4: Complete Guide to Setup, Use Cases & Modern Alternatives

If you’ve ever dug through a free proxy list or configured legacy automation tools, you’ve likely encountered SOCKS4. This older protocol still appears in countless proxy databases and bot configurations, even though newer options have long since surpassed it. Understanding how SOCKS4 works—and when to use something better—can save you hours of troubleshooting and help you make smarter infrastructure decisions.

What is a SOCKS4 Proxy Server?

SOCKS4 is an older but still-used socks proxy protocol that forwards TCP traffic between a client and a destination server without inspecting or modifying the data. While it lacks the features of modern alternatives, it remains relevant when working with legacy software or simple tunneling requirements.

Precise Definition

SOCKS4 is a TCP-only proxy protocol introduced in the mid-1990s to help applications traverse firewalls transparently. It typically runs on port 1080 and operates without built-in authentication or UDP support. When you connect through a SOCKS4 proxy server, your traffic is relayed through the socks server to the target destination, masking your real ip address from the endpoint.

The protocol defines two primary operations:

• CONNECT: Establishes outbound connections from the client to an application server
• BIND: Prepares the server for accepting inbound connections (less commonly used)

Where SOCKS4 Sits in the Network Stack

Unlike http proxies that operate at the application layer (Layer 7), SOCKS4 works at the session layer—sitting between your application and the transport layer. This positioning makes it protocol-agnostic: it can forward any TCP-based traffic, whether that’s web browsing, FTP, telnet, or custom protocols.

SOCKS4 won’t cache content, filter requests, or provide any security features on its own. It simply relays data after minimal access control checks.

Typical Use Cases

SOCKS4 is often used for:

• Legacy automation tools built before SOCKS5 became dominant
• Simple tunneling where only basic IP masking is needed
• Bots and scripts that don’t require authentication or UDP support
• Testing and development with older software

Modern providers, including SimplyNode, focus on https and SOCKS5 protocols because they offer more flexibility and security. However, understanding SOCKS4 helps when you’re working with older software or evaluating public proxies from a proxy list.

SOCKS4 Characteristics

SOCKS4 supports only TCP connections and has no built-in authentication standard. Many public proxies on a free proxy list are anonymous SOCKS4 servers shared across thousands of users. The protocol uses ip address values directly in requests—there’s no native domain name resolution unless you use the SOCKS4a extension.

This simplicity makes SOCKS4 fast and lightweight, but it also means:

• No way to verify user identity at the proxy level
• DNS queries happen locally, potentially exposing your browsing activity
• No support for UDP-based applications like VoIP or gaming

SOCKS5 Advantages

SOCKS5 addressed most of SOCKS4’s limitations. It supports both TCP and UDP, handles domain names natively, and includes username and password authentication—a feature widely used in paid proxy services for access control.

For high-concurrency applications, real-time tools, and modern apps requiring UDP, SOCKS5 is the clear choice. It’s also better suited for scenarios where you need to filter by country or implement granular user permissions.

HTTP/HTTPS Proxies Explained

HTTP proxies understand the HTTP protocol and can filter, cache, or modify traffic. They’re excellent for web browsing, web scraping, ad verification, and similar web-focused tasks.

HTTPS proxies (or SSL proxies) use the CONNECT method to tunnel encrypted connections to https websites. The proxy sees the destination hostname but cannot inspect the encrypted content—making them suitable for secure web traffic.

The limitation? HTTP proxies work only with HTTP/HTTPS traffic. They can’t handle other protocols like FTP, SSH, or custom TCP applications.

What About Encryption?

Neither SOCKS4 nor SOCKS5 encrypts traffic by itself. Encryption depends entirely on the application protocol—if you’re browsing an HTTPS website through a socks proxy, the connection to the site is encrypted, but the link between your client and the proxy may not be.

For this reason, businesses and data teams typically choose HTTPS or SOCKS5 residential/mobile proxies (like those from SimplyNode) for stability, authentication, geo-targeting, and compliance. Public proxies without encryption put your data at risk of interception.

How a SOCKS4 Proxy Server Works

Understanding the technical flow helps you troubleshoot connection issues and configure clients correctly. Here’s how a typical SOCKS4 connection works step by step.

Connection Flow

1. TCP Handshake: The client establishes a TCP connection to the SOCKS4 server, usually on port 1080.
2. Client Request: The client sends a SOCKS4 request packet containing:
   • Version identifier (0x04)
   • Command code (1 for CONNECT, 2 for BIND)
   • Destination port (2 bytes, network byte order)
   • Destination IP address (4 bytes, network byte order)
   • User ID string (null-terminated, optional)
3. Server Connection: The SOCKS4 server opens a TCP connection to the target server using the requested IP and port.
4. Server Response: If successful, the server returns a “request granted” reply (code 90). Other response codes indicate failures:
   • 91: Request rejected or failed
   • 92: Request rejected because SOCKS server cannot connect to identd
   • 93: Request rejected because the client program and identd report different user IDs
5. Data Relay: Once the connection is established, the proxy server relays traffic bidirectionally between client and target.

Supported Commands

SOCKS4 primarily supports the CONNECT command for establishing outbound connections. Unlike full SOCKS5, it doesn’t have robust BIND or UDP ASSOCIATE functionality. This makes it suitable for client-initiated connections but limited for applications requiring inbound connection handling.

Traffic Handling

Traffic passes through unmodified, which reduces overhead but also means:

• No content filtering or caching capabilities
• No built-in encryption, logging, or deep packet inspection
• Minimal processing—data is simply forwarded

This transparent approach is why SOCKS4 was originally designed for firewall traversal: it lets applications work across network boundaries without protocol-specific modifications.

SOCKS4a Extension

The SOCKS4a extension addresses one of SOCKS4’s biggest limitations: the requirement to specify IP addresses directly. With SOCKS4a, clients can send domain names instead of resolved IPs.

The format changes slightly—the IP address field is set to 0.0.0.x (where x is non-zero), and the domain name is appended after the null-terminated user ID. The proxy server then handles DNS resolution, which can help prevent DNS leaks and simplify client configuration.

Port Considerations

While 1080 is the standard port for SOCKS servers, a system administrator might configure non-standard ports for obfuscation or policy reasons. When setting up a client connection, always verify the correct port with your proxy provider or server configuration.

Common Use Cases for SOCKS4 Proxies

Although SOCKS4 is an older protocol, many tools and bots still support it—especially where only basic TCP tunneling is required. Here’s where you’ll encounter it in practice.

Historical and Current Applications

Legacy automation tools: Older SEO bots, traffic simulators, and link-checking programs often have SOCKS4 support built in from an era before SOCKS5 became dominant. These programs may not have been updated to support modern protocols.

Simple anonymization: For non-HTTPS applications requiring only basic IP masking, SOCKS4 provides straightforward hiding of your real IP address. The destination server sees the proxy’s IP instead of yours.

Lightweight scripts: Quick TCP tunneling without authentication overhead—useful for testing, development, or one-off requests where setup complexity matters more than security.

Why Public SOCKS4 Lists Exist

You’ve probably seen websites offering thousands of free SOCKS4 proxies. These public proxies typically come from:

• Scanned data center IPs and misconfigured servers
• Compromised systems unknowingly running proxy software
• Intentionally open proxies (sometimes for malicious purposes)

They’re attractive to users needing thousands of IPs briefly, but they’re fundamentally unreliable for any serious work. Proxies disappear, bandwidth is shared across many users, and many are already blocked or banned by major websites.

Professional Use: A Different Story

For web scraping, ad verification, price monitoring, brand protection, and market research, professional teams choose a different approach entirely. Instead of unreliable free proxy lists, they use:

• Residential proxies with IPs from real consumer ISPs
• Mobile proxies (4G/5G/LTE) for applications with strict rate limiting
• HTTPS or SOCKS5 with proper authentication and rotation

SimplyNode, for example, provides ethically-sourced residential and mobile proxies with SOCKS5 and HTTPS support—not SOCKS4—because modern use cases demand authentication, geo-targeting, and reliable connection speeds.

When SOCKS4 Still Makes Sense

Use SOCKS4 only when:

• Legacy software explicitly requires it and cannot be updated
• You’re running non-sensitive, low-value tasks where proxy reliability doesn’t matter
• You’re testing or learning about proxy protocols in a controlled environment

For anything else, SOCKS5 or HTTPS proxies are the suitable choice.

Common Issues and Troubleshooting

Connection timeouts: Dead or overloaded public SOCKS4 proxies are extremely common. Implement retry logic and proxy rotation in your code.

Access blocked: Major sites (Google, Instagram, Craigslist) actively block known proxy IPs. Public data-center SOCKS4 IPs have poor reputation and are frequently banned.

DNS leaks: With pure SOCKS4, DNS queries happen locally, potentially exposing your browsing activity to your ISP. SOCKS4a or SOCKS5 with remote DNS can help.

Protocol mismatch: Trying to connect with SOCKS5 client settings to a SOCKS4-only server (or vice versa) will fail silently or with cryptic errors. Verify the protocol version.

For reliable scraping and data collection, these issues make free proxy usage impractical. Professional proxy services with guaranteed uptime and IP rotation solve these problems systematically.

Limitations, Security Risks, and Modern Alternatives

Many professionals have moved away from SOCKS4 towards SOCKS5 and HTTPS residential/mobile proxies for good reasons. Understanding these limitations helps you make informed infrastructure decisions.

Key Limitations of SOCKS4

No authentication standard: Anyone who discovers your SOCKS4 server can use it. This makes access control difficult and dangerous if your server is exposed publicly. There’s no username or password mechanism in the base protocol.

No UDP support: Unlike SOCKS5, SOCKS4 cannot handle UDP traffic. This excludes:

• VoIP applications
• Video conferencing tools
• Online gaming
• DNS-over-UDP queries
• Real-time streaming protocols

IP-only addressing: Without the SOCKS4a extension, clients must resolve domain names locally and send only IP addresses. This creates DNS complications and inflexibility when working with dynamic hosts or CDNs.

Security Concerns

No built-in encryption: Traffic between client and proxy travels in plaintext unless the application itself uses TLS/SSL. This means:

• Login credentials can be intercepted
• Sensitive data is exposed on the network path
• Man-in-the-middle attacks are trivial

Public proxy risks: Random proxies from a free proxy list can:

• Log all your traffic for later analysis
• Inject malicious content into responses
• Be operated by threat actors harvesting credentials
• Already be compromised or part of botnets

Abuse potential: Open SOCKS proxies are routinely exploited for spam, port scanning, and attacks. Running one without proper protection risks getting your IP blacklisted across multiple databases.

Performance and Stability Issues

Public SOCKS4 lists are fundamentally unreliable because:

• IPs are crowd-sourced from scanned hosts worldwide
• Thousands of users share each proxy simultaneously
• Proxies appear and disappear unpredictably
• Bandwidth varies wildly based on source infrastructure
• Many are already blocked by target sites due to abuse

This makes them unsuitable for long-running scraping jobs, ad verification requiring consistent sessions, or brand protection where reliability is critical.

Modern Alternatives for Business Use

HTTPS and SOCKS5 residential proxies: These use IPs from real consumer ISPs, making requests appear as legitimate user traffic. They enjoy higher trust scores and better access to major sites that aggressively filter data center IPs.

Mobile (4G/5G/LTE) proxies: Ideal for apps and services that heavily rate-limit or block traditional proxies. Mobile IPs rotate naturally as devices change cell towers, providing built-in rotation.

SimplyNode’s Approach

SimplyNode focuses on HTTPS and SOCKS5 residential and mobile proxies with ethically-sourced IPs—the protocols that actually work for modern use cases.

Key features relevant to current SOCKS4 users considering an upgrade:

• Rotating and sticky sessions: Choose automatic rotation or maintain the same IP for session continuity
• Country and city-level geo-targeting: Filter requests by specific locations
• Pay-as-you-go pricing: No long-term commitment or expiration
• No bandwidth limits per IP: Use what you need
• Support for web scraping, price monitoring, ad verification, and brand protection

This approach eliminates the reliability problems, security risks, and censorship issues that plague public SOCKS4 proxies.

Practical Guidance

Use SOCKS4 only when:

• Legacy tools explicitly require it and cannot be updated
• You’re running non-critical experiments or learning exercises
• The alternative is not having proxy access at all

For production workloads and sensitive data:

• Migrate to managed HTTPS/SOCKS5 residential or mobile proxies
• Ensure proper authentication is in place
• Use providers with clear ethical sourcing and compliance policies

The speed advantage of SOCKS4’s minimalism is irrelevant when connections fail 50% of the time or your requests get blocked. Reliability and IP quality matter far more than protocol overhead.

Key Takeaways

• SOCKS4 is a TCP-only proxy protocol from the 1990s that still appears in legacy tools and free proxy lists
• It lacks authentication, UDP support, and encryption—significant limitations for modern security requirements
• Public SOCKS4 proxies are unreliable, shared across many users, and frequently blocked by major sites
• SOCKS5 and HTTPS proxies address these limitations with authentication, UDP support, and better compatibility
• For professional web scraping, ad verification, price monitoring, and brand protection, residential and mobile proxies are the industry standard
• Self-hosting SOCKS4 is possible for testing but requires careful security hardening

Moving Forward

SOCKS4 served its purpose in the early days of internet proxy protocols, but modern workloads demand more. The protocol’s lack of authentication, encryption, and UDP support makes it unsuitable for anything beyond legacy compatibility and low-stakes experimentation.

If you’re still using public SOCKS4 proxies for serious work, you’re likely experiencing frustrating connection failures, blocked requests, and inconsistent performance. The path forward is clear: HTTPS and SOCKS5 residential proxies with proper authentication, rotation, and geo-targeting capabilities.

SimplyNode offers a straightforward way to test modern proxy infrastructure. With pay-as-you-go pricing, no expiration, and no long-term commitment, you can compare SOCKS5/HTTPS residential or mobile proxies against your current SOCKS4 setup without risk. Start with a small traffic package, run your existing scripts, and see the difference in reliability and success rates.

Ready to leave connection timeouts and blocked requests behind? Get Started with SimplyNode’s residential proxy network and experience what modern proxy infrastructure actually looks like.