Zscaler Speed Test

When you're working remotely or accessing cloud applications, a reliable and fast internet connection is crucial. If you're using Zscaler, you might wonder how it impacts your network performance. A zscaler speed test is the best way to determine the real-world effect of this security platform on your internet connection. While Zscaler enhances security by inspecting your traffic, it can introduce latency or affect throughput, making a dedicated speed test essential for understanding your actual experience.

What is Zscaler and Why Does It Matter for Speed?

Zscaler is a cloud security platform that provides secure access to applications and data for users anywhere, on any device. Unlike traditional perimeter security, Zscaler operates as a "security service edge" (SSE), sitting between your users and the internet or cloud applications. This means all your internet-bound traffic is routed through the Zscaler cloud for inspection, policy enforcement, and threat prevention before reaching its destination.

This architecture, while highly effective for security, inherently changes your network's traffic path. Instead of directly accessing a website, your request first goes to a Zscaler data center, is inspected, and then forwarded. This process can add a small amount of latency and potentially affect your overall internet speed, which a zscaler speed test can help you quantify.

Is Zscaler slowing down internet speed?

Yes, Zscaler can potentially slow down your internet speed, but often for good reasons related to security and policy enforcement. The degree of impact depends on several factors, including your geographical proximity to the nearest Zscaler data center, the specific security policies applied, the amount of traffic inspection required, and your local network conditions. For instance, if your traffic has to travel a long distance to a Zscaler node, latency will increase. Similarly, intensive deep packet inspection for malware or data loss prevention can add processing time.

To accurately assess if Zscaler is impacting your speed, you should perform a zscaler speed test both with and without Zscaler enabled (if possible and approved by your IT department). This direct comparison will highlight any performance differences. When you run a Zscaler speed test, pay attention to not just download and upload speeds, but also latency (ping) and jitter, as these often reveal more about the Zscaler experience.

Typical Zscaler Performance Metrics to Monitor

Understanding what constitutes "good" performance with Zscaler involves looking at more than just raw bandwidth. Latency and jitter are key indicators of a smooth user experience, especially for real-time applications.

Metric	Description	Ideal Range (with Zscaler)	Potential Impact of Zscaler
Latency (Ping)	Time it takes for a data packet to travel from your device to a server and back.	20-80 ms	Can increase due to traffic routing to Zscaler PoPs
Download Speed	Rate at which data is transferred from the internet to your device.	Varies (e.g., 50-500 Mbps)	May slightly decrease due to inspection overhead
Upload Speed	Rate at which data is transferred from your device to the internet.	Varies (e.g., 10-100 Mbps)	Similar to download, slight decrease possible
Jitter	Variation in the delay of received packets, crucial for real-time apps.	< 30 ms	Can increase if traffic path is unstable or congested
Packet Loss	Percentage of data packets that fail to reach their destination.	0%	High packet loss indicates network issues

Understanding Your Zscaler Speed Test Results

When you run a zscaler speed test, don't just look at the final download number. Here's how to interpret the results:

Latency (Ping): This is often the most noticeable impact of Zscaler. If your ping times are consistently high (over 100ms for general browsing, or over 50ms for gaming/video calls), Zscaler might be adding significant overhead. Compare this to a speed test run directly to the internet (without Zscaler) to see the difference.
Download/Upload Speed: While Zscaler's primary function isn't to improve speed, it shouldn't drastically reduce it. A minor reduction (e.g., 5-15%) might be acceptable given the security benefits. However, if your 200 Mbps connection drops to 50 Mbps with Zscaler, there's likely an issue.
Jitter and Packet Loss: These are critical for real-time applications like video conferencing, VoIP, and online gaming. High jitter or any packet loss can make these experiences choppy and frustrating, even if your raw download speed looks good.

Remember, the goal of a zscaler speed test is to establish a baseline and identify significant deviations. If your Zscaler performance is consistently poor, it's time to investigate further.

Is Zscaler just a VPN?

No, Zscaler is fundamentally different from a traditional Virtual Private Network (VPN), although both can provide secure remote access. Understanding this distinction is key to comprehending its network impact.

A traditional VPN creates an encrypted tunnel from your device back to your corporate network. All your internet traffic then exits through the corporate firewall, regardless of whether it's destined for an internal resource or the public internet. This model is often called "hairpinning" because traffic goes out and then back in, which can introduce significant latency and bandwidth bottlenecks for cloud-first organizations.

Zscaler, on the other hand, operates on a "cloud-native proxy" model. It's part of a Security Service Edge (SSE) platform. When you connect via Zscaler Internet Access (ZIA), your traffic is directed to the nearest Zscaler cloud data center (Point of Presence or PoP). At this PoP, Zscaler acts as a secure intermediary, inspecting traffic, enforcing policies, and preventing threats. Importantly, Zscaler allows for "local breakouts" to the internet, meaning your traffic doesn't need to go back to your corporate data center for internet access. Instead, it securely reaches its destination directly from the Zscaler cloud.

This architectural difference means:

Security: Zscaler provides security at the edge, closer to the user and the application, rather than relying on a centralized corporate firewall.
Performance: By allowing local breakouts, Zscaler aims to reduce latency compared to traditional VPN hairpinning, especially for internet-bound traffic. However, the overhead of inspection and routing to the Zscaler cloud can still impact raw speed, as shown by a zscaler speed test.
Scalability: Zscaler's cloud-native architecture scales globally, handling millions of users and billions of transactions without the need for on-premises hardware.

How to troubleshoot Zscaler slowness issue?

If you suspect Zscaler is causing slowness, a systematic troubleshooting approach is essential. Start by isolating the issue to determine if Zscaler is indeed the root cause or if other network factors are at play.

Here’s a step-by-step guide to troubleshoot Zscaler slowness:

Check Your Local Network:
- Restart your router/modem: A simple reboot can resolve many local network glitches.
- Test other devices: See if other devices on your network experience similar slowness. If they do, the issue is likely with your local Wi-Fi or ISP, not Zscaler.
- Wired vs. Wireless: Connect your device directly to your router with an Ethernet cable. If performance improves, your Wi-Fi signal might be weak or congested.
Run a Zscaler Speed Test (and a Non-Zscaler Comparison):
- With Zscaler: Use standard speed test sites (e.g., Speedtest.net, Fast.com) while connected through Zscaler. Note down download, upload, latency, and jitter.
- Without Zscaler (if permitted): Temporarily disconnect from Zscaler (if your IT policy allows) and run the same speed tests. Compare the results. A significant difference points towards Zscaler or its configuration.
- Zscaler-specific tools: Your IT department might provide access to Zscaler's own diagnostic tools or recommended speed test servers to get the most accurate picture of Zscaler's performance.
Examine Zscaler Logs and Dashboard (IT/Admin Only):
- If you have administrative access or can work with your IT team, check the Zscaler dashboard. Look for:
  - User Traffic Logs: Identify specific applications or websites consuming high bandwidth or experiencing high latency.
  - Policy Issues: Ensure no overly restrictive policies are inadvertently blocking or slowing legitimate traffic.
  - PoP Selection: Verify that your traffic is being routed to the closest and least congested Zscaler Point of Presence (PoP).
Bypass Zscaler Temporarily (with Caution):
- Only do this if explicitly allowed by your IT department. Temporarily bypassing Zscaler can confirm if the platform is the cause. If performance immediately improves when bypassed, the issue lies within Zscaler's configuration or a specific policy.
Contact IT Support / Zscaler Support:
- If you've gone through these steps and still experience issues, gather your findings (speed test results, specific applications affected, timestamps) and contact your organization's IT support or Zscaler's technical support. They can perform deeper diagnostics.

Common Network Activities and Zscaler Impact

Different online activities have varying sensitivities to network performance. Understanding this can help you pinpoint specific issues reported by a zscaler speed test.

Activity	Bandwidth Req. (Typical)	Latency Sensitivity	Zscaler Impact Considerations
Web Browsing	Low (1-5 Mbps)	Moderate	Minor impact usually. High latency can make pages load slowly.
Email/Messaging	Very Low (0.1-1 Mbps)	Low	Negligible impact on speed. Security scanning is primary Zscaler function.
HD Video Streaming	5-25 Mbps (1080p-4K)	Moderate	Can be affected by throughput. If Zscaler causes drops, streaming quality may degrade (e.g., lower resolution).
Video Conferencing	2-10 Mbps (HD)	High	Very sensitive to latency and jitter. High values cause pixelation, freezing, and audio drops.
Online Gaming	5-50 Mbps	Very High	High latency (ping) is a "game-changer." Any increase can lead to noticeable lag and poor responsiveness.
Large Downloads	High (25+ Mbps)	Low	Primarily affected by raw download speed (throughput). Zscaler's inspection overhead can extend download times.

For activities like HD video streaming, if your Zscaler speed test shows significant throughput drops, you might experience lower resolution or buffering. While Zscaler focuses on network performance, the visual experience also depends on your display settings. If you're struggling with perceived quality, consider checking your monitor's settings. Our free Aspect Ratio Calculator can help you ensure your video content is displayed correctly, preventing stretched or cropped images, and making the most of the bandwidth you have.

Optimizing Your Experience with Zscaler

While Zscaler's primary role is security, there are ways to optimize your experience and mitigate potential speed impacts:

Location Awareness: Zscaler automatically routes you to the nearest PoP, but sometimes this can be suboptimal. Ensure your device's location services are accurate, or work with IT to confirm the best PoP selection.
Policy Optimization: Overly aggressive or redundant security policies can add unnecessary processing time. IT teams should regularly review and optimize security policies to balance security with performance.
Local Breakouts: For trusted, high-bandwidth applications (e.g., Microsoft 365, Zoom), Zscaler often allows for direct local breakouts, bypassing some inspection for better performance. Your IT team configures these.
Client Connector Updates: Ensure your Zscaler Client Connector is always up-to-date. Newer versions often include performance enhancements and bug fixes.
Network Health: Maintain a healthy local network. A strong Wi-Fi signal, up-to-date router firmware, and sufficient local bandwidth are foundational for good Zscaler performance.

Even with Zscaler optimizing network traffic, your overall viewing experience for streaming and video content can be further enhanced by ensuring your display settings are correct. For instance, if you're streaming a movie and notice distortion, it might not just be a bandwidth issue; your screen's aspect ratio might be incorrect. Use our Aspect Ratio Calculator to quickly determine the right settings for your display and content, ensuring you get the sharpest and most accurate image possible, even if your network speed isn't absolutely top-tier.

Conclusion

A zscaler speed test is a crucial diagnostic tool for anyone using the Zscaler platform. While Zscaler provides unparalleled security by inspecting all internet-bound traffic, this process can introduce a degree of latency or affect throughput. It's important to understand that Zscaler is not merely a VPN but a sophisticated cloud security platform designed to protect your network at the edge. By carefully analyzing your speed test results, distinguishing between Zscaler's impact and other network issues, and troubleshooting systematically, you can ensure a secure and acceptably fast internet experience. Regular monitoring and optimization, often in collaboration with your IT team, will help you get the most out of your Zscaler deployment.