Zscaler and DNS over HTTPS (DoH): A Comprehensive Guide

DNS over HTTPS (DoH) is a privacy-enhancing protocol that encrypts DNS queries, shielding them from potential eavesdroppers and manipulation. Zscaler, a leading cybersecurity company, offers its own approach to DNS security and management. This guide will delve into the interplay between Zscaler's security solutions and DoH, exploring its benefits, limitations, and implications for organizations.

Understanding DNS over HTTPS (DoH)

Traditionally, DNS queries are sent in plain text over UDP port 53. This makes them vulnerable to various attacks, including DNS spoofing, cache poisoning, and surveillance. DoH addresses this vulnerability by encapsulating DNS queries within an HTTPS connection (port 443), leveraging the security and encryption features of HTTPS. This means that DNS requests are encrypted, making them much harder to intercept and analyze.

The key benefits of DoH include:

• Enhanced Privacy: Prevents third parties from observing your DNS queries, protecting your browsing history and online activities.
• Increased Security: Protects against DNS spoofing and other attacks that target unencrypted DNS traffic.
• Improved Performance: In some cases, DoH can lead to faster DNS resolution due to optimized server infrastructure.

Zscaler's Approach to DNS Security

Zscaler doesn't directly support or offer a standalone DoH client. Instead, Zscaler's security cloud acts as a secure DNS resolver for its users. Its approach focuses on providing comprehensive security and performance through its secure web gateway and other security services. Zscaler's DNS resolution is integrated into its broader security platform, providing:

• DNS Security Extensions (DNSSEC): Zscaler leverages DNSSEC to ensure the authenticity and integrity of DNS responses, protecting against DNS spoofing.
• Threat Intelligence: Zscaler's DNS resolution is powered by its extensive threat intelligence, enabling it to block malicious domains and prevent users from accessing harmful websites.
• Centralized Management: Administrators have complete control over DNS settings and policies through Zscaler's management console.
• Performance Optimization: Zscaler's globally distributed infrastructure optimizes DNS resolution times, ensuring fast and reliable access to online resources.

How Zscaler Interacts with DoH (Indirectly)

While Zscaler doesn't explicitly use DoH as a protocol, its security architecture inherently provides many of the same benefits. Because all DNS traffic is routed through Zscaler's security cloud, it's effectively encrypted and protected. The organization's traffic never leaves the Zscaler network, so the benefits of encryption are maximized.

Furthermore, because Zscaler performs DNS resolution within its own secure infrastructure, it can apply its threat intelligence, security policies and filters, offering enhanced protection that a standalone DoH implementation might lack.

Advantages of using Zscaler over a standalone DoH solution:

• Comprehensive security features: Zscaler's security is not limited to DNS; it provides a comprehensive suite of security services including firewall, intrusion prevention, and data loss prevention.
• Centralized management: Manage all security aspects from a single console, simplifying administration.
• Threat intelligence integration: Leverage Zscaler's threat intelligence to block malicious websites and protect against advanced threats.
• Global network optimization: Benefit from Zscaler's globally distributed infrastructure for enhanced performance and reliability.

Considerations and Limitations

While Zscaler offers significant security and performance advantages, it's crucial to consider the following:

• Increased Complexity: Implementing and managing Zscaler requires technical expertise and may be more complex than configuring a standalone DoH client.
• Vendor Lock-in: Relying on Zscaler introduces a degree of vendor lock-in, potentially limiting flexibility in the future.
• Cost: Zscaler is a subscription-based service, incurring ongoing costs.

Conclusion

The combination of Zscaler's security platform and the inherent security benefits of DoH provides organizations with a robust and secure DNS solution. While Zscaler doesn't implement DoH directly, its comprehensive approach provides comparable privacy and security enhancements, while also integrating crucial security features beyond encryption. The choice between a standalone DoH solution and Zscaler depends on the specific needs and priorities of the organization, weighing factors such as budget, technical expertise, and the required level of security control.