Navigating Encrypted Client Hello and DNS over HTTPS in School Filtering

As schools strive to create safe digital environments, new privacy technologies like Encrypted Client Hello (ECH) and DNS over HTTPS (DoH) pose challenges for traditional content filtering methods. These privacy protocols are designed to enhance user privacy, but they also limit visibility into online activity—a potential roadblock for K-12 administrators working to maintain secure, focused online learning spaces.

While these privacy advancements challenge many filtering solutions, Lightspeed Systems’ unique approach to content filtering ensures that ECH and DoH protocols do not disrupt our ability to provide safe, reliable web access for schools. Here’s a look at what ECH and DoH mean for school filtering and how Lightspeed’s advanced filtering methods offer robust, uninterrupted protection in the face of new privacy standards.

Understanding Encrypted Client Hello (ECH)

ECH is a new standard that protects user privacy by encrypting the initial “client hello” step in the TLS (Transport Layer Security) handshake. This step typically reveals the domain name a user is trying to access, allowing filtering solutions to monitor and block content. However, ECH conceals this domain information, making it difficult for systems that rely on intercepting this step—such as packet filters and inline inspection filters—to identify and filter certain websites.

What DNS over HTTPS (DoH) Means for Filtering

DoH is another privacy protocol that obscures DNS requests, the queries that convert domain names into IP addresses. By encrypting DNS traffic, DoH prevents traditional DNS-based filters from reading the details of users’ requests, making it harder for schools to restrict access to specific websites.

Both ECH and DoH are designed to protect privacy but create significant obstacles for traditional filtering methods, especially those that don’t use Man-in-the-Middle (MITM) proxying.

Challenges Posed by ECH and DoH for School Filters

For many school filtering solutions, ECH and DoH significantly reduce their effectiveness:

• Packet Filtering Solutions: ECH makes it difficult for packet-filtering systems (often used in firewalls) to see domain details, as these systems typically inspect unencrypted information to determine the websites being accessed.
• Inline Filters and Firewalls: Filters that rely on packet sniffing and SNI (Server Name Indication) details to determine website addresses lose visibility due to ECH. With this information hidden, such solutions cannot effectively monitor or block specific content.
• DNS-Based Filters: DoH can limit the effectiveness of DNS-based filters by encrypting DNS requests, making it challenging for schools to monitor or restrict access to inappropriate websites.

Lightspeed Systems: A Filtering Solution Designed to Withstand Privacy Protocols

Unlike many traditional systems, Lightspeed Systems is prepared for the privacy advancements that ECH and DoH represent. Here’s how:

1. Lightspeed’s TLS Handshake Process: Lightspeed Systems completes the TLS handshake on behalf of the user, effectively “becoming” the user in the eyes of the web server. This approach maintains visibility into the requested domains, even with ECH in place, allowing Lightspeed to continue filtering effectively without interruption.
2. DNS-Based Filtering Independent of ECH: Lightspeed’s DNS filters, including solutions like SmartShield, operate independently of the TLS layer, focusing on DNS requests rather than packet inspection. This means that ECH’s encryption of the client hello stage does not impact these filters, enabling schools to maintain reliable and secure filtering.
3. Blocking DNS over HTTPS (DoH): Since DoH can obscure DNS requests, Lightspeed proactively prevents or blocks DoH connections. By doing so, Lightspeed ensures that its DNS-based filters retain visibility into user requests, allowing administrators to effectively control and monitor online content.

Why This Matters for U.S. School Districts

As privacy technology continues to evolve, school districts must have filtering solutions that adapt to these changes without compromising student safety. Lightspeed’s filtering methods not only keep pace with privacy advancements like ECH and DoH but also maintain reliable control over online content, ensuring that students are safe and focused during online learning.

Moving Forward with Confidence

At Lightspeed Systems, we understand that privacy and security are evolving, and we remain committed to providing school districts with future-ready filtering solutions. With our advanced approach to content filtering, schools can trust that they have the tools they need to navigate new privacy protocols and protect students effectively.

For more information about how Lightspeed Systems can support your school district in navigating ECH, DoH, and other privacy advancements, contact us or explore our resource library. Together, we can help maintain a safe and productive digital environment for every student.