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Ditch the Explicit Proxy & PAC File Hassle: A Simpler, More Secure Solution

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IAIN LEITER
June 23, 2025 - 4 Min de lectura

For over 25 years, organizations have struggled with the complexities of managing explicit proxies and PAC (Proxy Auto-Configuration) files. Despite advancements elsewhere in network and security technology, many companies continue to grapple with operational inefficiencies, incomplete security coverage, and costly legacy architecture.

There is a far easier way to achieve secure and effective traffic forwarding. Zscaler Client Connector and Zero Trust Exchange (ZTE) offer a globally distributed Security Service Edge (SSE) and Secure Access Service Edge (SASE) platform, delivering significant improvements in operational simplicity, cost reduction, performance, and security.

Figure 1 - A single agent called Client Connector forwards traffic to the Zero Trust Exchange where all advanced features (including transparent proxy) are applied.
Figure 1 - A single agent called Client Connector forwards traffic to the Zero Trust Exchange where all advanced features (including transparent proxy) are applied.

 

This article will explore the challenges of relying on explicit proxies and PAC files while highlighting how Zscaler’s Client Connector streamlines traffic forwarding and transforms enterprise security.

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Figure 2 – Explicit Proxy Compared to Client Connector

 

Explicit Proxy & PAC File Pain Points

After decades of use, explicit proxies and PAC files have revealed serious limitations across multiple dimensions of IT operations and cybersecurity. Common pain points include:

  1. Cumbersome Maintenance and Management
    PAC files are inherently difficult to maintain and update and can create bottlenecks without proper oversight.
  2. Major Security Gaps
    Explicit proxies protect only web traffic, leaving other ports, protocols, and DNS traffic exposed to potential threats.
  3. Vulnerability to Tampering and Bypass
    PAC files are inherently susceptible to tampering, introducing a major security risk to any enterprise.
  4. Incompatibility with Advanced Security Integrations
    As organizations adopt modern detection and response tools—including Endpoint Detection and Response (EDR)—explicit proxies fail to support seamless integrations.

These challenges add significant complexity to operations while exposing enterprises to modern, multi-vector cybersecurity threats. Fortunately, Zscaler offers a simpler and more secure approach.

 

Figure 3 – Table Comparison of Features Suppo
Figure 3 – Table Comparison of Features Supported

 

Figure 4 – Endpoint Client Consolidation
Figure 4 – Endpoint Client Consolidation

 

Cost Reduction with Client Connector

Organizations that adopt Zscaler's Client Connector benefit from substantial cost efficiencies through consolidation and the elimination of redundant legacy systems.

Key Cost-Saving Opportunities

  • Consolidate legacy technologies, replacing multiple tools with a single SSE agent.
  • Eliminate VPN clients and standalone endpoint solutions, including those for DLP and DNS security.
  • Streamline endpoint performance monitoring into one integrated solution, such as Zscaler Digital Experience Monitoring (see Figure 5).
  • Reduce reliance on MPLS circuits and expensive Express Routes.
  • Lower Virtual Desktop Infrastructure (VDI) costs for published apps and third-party access.
  • Avoid physical and virtual firewall licenses, cutting expenses significantly.

By consolidating disparate tools into a single platform, enterprises not only save money but also reduce management complexity—ensuring security policies are applied uniformly across the organization.

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Figure 5 – Zscaler Digital Experience Monitoring (Part of Client Connector)

 

Lower Operational Overhead with Client Connector

Zscaler's Client Connector reduces the operational burden tied to managing explicit proxies and associated security tools. Streamlined management processes and advanced automation allow IT teams to focus on higher-value projects.

Key Efficiency Gains

  • Deploy a single traffic-forwarding agent compatible with all device types and operating systems.
  • Simplify network policies by removing dependence on subnet- or VLAN-specific configurations.
  • Consolidate security management under a single point of control, accessible through a web console or API.
  • Offload intensive processes (e.g., TLS/SSL inspection, deep packet inspection, and intrusion prevention) to the scalable Zscaler cloud.
  • Eliminate reliance on cumbersome PAC files, often exceeding 1,000 lines of code and prone to errors.
  • Proactively diagnose and resolve performance issues using built-in digital experience monitoring (Figure 5).

Transparent Proxy functionality integrated into Client Connector reduces fragmentation, allowing for seamless policy implementation without relying on a patchwork of outdated proxy tools. This level of operational simplicity significantly reduces both time-to-management and time-to-resolution for security teams.

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Figure 6 – Zscaler Client Connector Enables Integration with Imprivata (Healthcare Use Case) 

 

Enhanced Security with Client Connector

Unlike explicit proxies, Zscaler's Client Connector offers robust, identity-driven security for all enterprise traffic—not just web traffic. This all-encompassing approach eliminates critical gaps in coverage, ensuring organizations stay protected in a rapidly evolving threat landscape.

Key Features Enhancing Security

  • Identity-based policies apply universally across all security controls, ensuring consistency.
  • Comprehensive coverage for all ports and protocols, eliminating blind spots.
  • Single-pane-of-glass management for Data Loss Prevention (DLP) policies across endpoint, email, inline, and CASB channels.
  • Tamper-resistant agent technology, protected against PAC file manipulation.
  • DNS visibility and control ensure that no traffic is left unmonitored or unprotected.
  • Built-in deception techniques, including endpoint lures, proactively detect and mitigate lateral movement threats.
  • Zero Trust device posture checks enforce compliance with organizational security standards (e.g., processes, firewalls, and domain policies).
  • Seamless integrations with advanced detection platforms like EDR enhance overall security effectiveness.

With these capabilities, Zscaler provides comprehensive protection for organizations, avoiding the fragmented and limited protections offered by legacy proxies and PAC files.

Summary

For organizations still relying on explicit proxies and PAC files, Zscaler provides a powerful alternative. Client Connector, working with the Zero Trust Exchange, enables enterprises to achieve:

  • Cost Reduction and Consolidation through the elimination of redundant tools and outdated architecture.
  • Simpler Operations with a unified management platform, advanced role-based controls, and cloud-powered automation.
  • Enhanced Security that extends across all ports, protocols, locations, and user devices—all with identity-based consistency.

Whether it’s simplifying IT management, achieving significant cost savings, or improving security posture, Zscaler delivers tangible results.

For industries like healthcare, where regulatory compliance is critical (see Figure 6: Imprivata Integration Use Case), the advantages of Zscaler’s end-to-end solution are even more pronounced. By replacing explicit proxies with Client Connector, healthcare providers can reduce operational friction, protect sensitive data, and meet strict regulatory standards.

Say goodbye to PAC file purgatory and embrace a simpler, more secure, and cost-effective future with Zscaler.

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