Is Zscaler VPN also a proxy server?

In short, Zscaler is not a traditional VPN, nor is it just a simple proxy server. Instead, it’s a comprehensive cloud security platform that performs the functions of both, but in a fundamentally more modern and secure way. Zscaler Internet Access (ZIA) acts like a highly advanced, cloud-based proxy for all internet traffic, while Zscaler Private Access (ZPA) serves as a replacement for the traditional VPN, offering more secure access to internal applications. To call it just one or the other would be an oversimplification of its architecture.

To truly understand this, it helps to look at how Zscaler’s two core products address the functions traditionally handled by proxies and VPNs.

The Proxy Function: Zscaler Internet Access (ZIA)

Traditionally, a proxy server sits within a company’s network, acting as an intermediary between employees and the internet. When a user wants to visit a website, the request goes to the proxy first. The proxy then inspects the request, applies security policies, and forwards it to the internet on the user’s behalf. This is done to filter content, block threats, and prevent data loss.

Zscaler Internet Access (ZIA) takes this concept and moves it to the cloud. Instead of a physical appliance in an office, ZIA is a globally distributed security cloud. When a user, whether in the office or working remotely, connects to the internet, their traffic is first routed to the nearest Zscaler data center. This is where ZIA acts as a sophisticated “proxy in the cloud.”

Inside the Zscaler cloud, a full security stack is applied to the user’s traffic. This includes:

• URL Filtering: Blocking access to malicious or non-compliant websites.
• Threat Protection: Inspecting for malware, ransomware, and other advanced threats.
• Full SSL/TLS Inspection: Decrypting encrypted traffic to find hidden threats, a task that often overwhelms traditional on-premise proxies.
• Data Loss Prevention (DLP): Ensuring sensitive company data isn’t being exfiltrated.

So, in this context, ZIA is performing the role of a proxy server, but on a massive, scalable, and globally accessible level. It’s more accurately called a Secure Web Gateway (SWG) or a “security cloud,” but its core function is rooted in the proxy architecture.

The VPN Replacement: Zscaler Private Access (ZPA)

A traditional VPN (Virtual Private Network) is designed to solve a different problem: giving remote users access to applications and resources located inside a private corporate network. A VPN creates an encrypted tunnel that essentially places the remote user on the company network, granting them broad access as if they were sitting in the office. While effective, this model is now seen as a security risk because if a user’s device is compromised, an attacker can gain access to the entire network.

This is where Zscaler Private Access (ZPA) comes in. ZPA is Zscaler’s solution for what is known as Zero Trust Network Access (ZTNA). It is designed to completely replace the need for traditional remote access VPNs.

ZPA works on a fundamentally different principle. Instead of connecting a user to the network, ZPA connects a specific, authenticated user directly to a specific, authorized application. This connection is brokered by the Zscaler cloud, and the application is never exposed to the public internet. The user is never placed on the network, which dramatically reduces the attack surface. An authenticated user can access App A and App B, but they remain completely unaware of and unable to connect to App C.

Therefore, ZPA fulfills the purpose of a VPN—providing secure access to private applications—but it does so without the associated network-level risks. It is a VPN alternative, not a VPN itself.

Conclusion: A Platform Beyond Simple Labels

Calling Zscaler a VPN or a proxy is like calling a modern smartphone just a phone or a camera. It does those things, but the label fails to capture the full scope of what it is.

Zscaler uses a proxy-like architecture in its ZIA product to secure all internet-bound traffic for its users. Simultaneously, it uses its ZPA product to replace the traditional VPN, providing more granular and secure access to internal applications based on a Zero Trust model. Together, these services form a modern security platform that is better suited for today’s world of remote work, cloud applications, and sophisticated cyber threats.