NextDNS Protocol Comparison: DoH, DoQ, and DoT

Exploring the Stability and Performance of DNS Encryption Protocols

Key Insights

DoH (DNS over HTTPS) offers strong stability in complex network environments due to its use of standard HTTPS ports.
DoQ (DNS over QUIC) presents promising performance with its advanced handling of network loss, though its support is still evolving.
DoT (DNS over TLS) is dependable in stable networks but may be susceptible to port-based blocking and detection.

Introduction to DNS Encryption Protocols in NextDNS

NextDNS supports three main DNS encryption protocols: DNS over HTTPS (DoH), DNS over TLS (DoT), and DNS over QUIC (DoQ). Each protocol offers a different balance between stability, performance, and ease of deployment based on your network configuration and device capabilities. The essential consideration is to select the protocol that aligns best with your operational environment. In this analysis, we explore the distinct characteristics, strengths, and potential drawbacks of these protocols, focusing on their stability, which is a key factor for reliable DNS resolution.

Detailed Protocol Analysis

Understanding DoH (DNS over HTTPS)

Overview and Mechanism

DoH encapsulates DNS queries within HTTPS traffic, effectively hiding them among other secure web communications. By using TCP port 443—the same port used for regular HTTPS traffic—DoH traffic blends into the typical internet traffic, making it more difficult for ISPs or network administrators to block or inspect DNS queries.

Stability

The stability of DoH is largely attributable to its use of a widely adopted protocol (HTTPS). Many operating systems and devices have mature implementations for HTTPS, which means that after the initial connection establishment, data transfer can be both secure and resilient. This ensures that even in environments with heavy surveillance or content filtering, DoH remains reliable. Additionally, the substantial back-end infrastructure supporting HTTPS worldwide contributes to eliminating disruptions.

Performance Considerations

While DoH has many advantages, there are trade-offs regarding resource usage and initial connection latency. Establishing a secure HTTPS connection can incur a higher resource cost, which might result in a slight delay during the first DNS query. Nonetheless, many clients are now optimized to use HTTP/3, further reducing latency and improving data transfer in persistent connections. This ongoing development in HTTP and HTTPS protocols contributes to the enhanced performance of DoH in evolving network conditions.

Exploring DoT (DNS over TLS)

Overview and Mechanism

DoT delivers encrypted DNS queries by wrapping them in TLS over a dedicated port (TCP/853). This separation of DNS traffic from standard web traffic can simplify implementation on some devices and reduce complexity in the protocol stack compared to DoH.

Stability

When it comes to stability, DoT performs reliably in stable and controlled network environments. Since it operates on a dedicated port, performance is predictably consistent under benign network conditions. However, the use of TCP/853 makes it more conspicuous to network administrators and potential filtering mechanisms. In scenarios where port-based blocking is enforced—such as in certain corporate networks or regions with strict internet controls—the performance and stability of DoT can suffer.

Performance Considerations

In terms of latency, DoT can be very efficient provided that the network does not interfere with the dedicated port. Some studies have indicated that in optimal conditions, DoT might offer slightly lower delays compared to DoH; however, this advantage can quickly be negated in environments where port-based traffic shaping or blocking is prevalent.

Assessing DoQ (DNS over QUIC)

Overview and Mechanism

DoQ represents the next generation of DNS encryption, utilizing the QUIC protocol. QUIC, which is built on top of UDP, offers inherent advantages such as reduced connection setup times and improved resiliency against packet loss. While its theoretical performance is promising, DoQ is still in a stage where widespread support is being developed and implemented.

Stability

DoQ is designed to deliver high performance, particularly in networks with frequent packet loss or congestion. Its reliance on QUIC allows more efficient handling of multiple simultaneous connections and faster reconnection strategies. Despite these benefits, the maturity of DoQ implementations varies, and in some scenarios, its stability may not yet match that of the more established DoH, especially on older or limited devices.

Performance Considerations

In theory, DoQ should outperform both DoH and DoT in reducing latency, particularly in networks where UDP’s benefits can be fully utilized. Its ability to perform multiplexed connections without the overhead of multiple TCP handshakes means it can more effectively manage bursts of DNS queries. Nonetheless, because DoQ adoption is still maturing, client and server support might limit its practical application until the ecosystem catches up.

Comparative Stability Analysis

Evaluating the stability of DoH, DoT, and DoQ in NextDNS depends on several factors such as network infrastructure, endpoint support, and use case scenarios. In general:

Protocol	Stability	Network Concealment	Device Compatibility
DoH	Highly stable in diverse network environments; seamlessly integrates with HTTPS infrastructure.	Excellent, due to the use of TCP/443 common to HTTPS traffic.	Broadly supported by modern devices and operating systems.
DoT	Stable in predictable, controlled network conditions; may face issues in environments with blocking.	Moderate; relies on TCP/853 which can be flagged by firewalls.	Supported on many platforms but may require specific configurations.
DoQ	Promising high stability, especially in handling packet loss; real-world usage still evolving.	Good, uses UDP and QUIC to reduce detection; however, its novelty can affect deployment.	Adoption is growing but not yet as universally available as DoH.

The table above integrates key aspects of stability, network concealment, and device compatibility, highlighting the differences in how each protocol manages DNS queries. It is clear that while DoH and DoT benefit from maturity and widespread deployment, DoQ offers an innovative approach that could eventually deliver superior stability under certain conditions.

Factors Influencing Protocol Stability

Network Configuration

One of the major determinants of DNS protocol stability is the configuration of the network. For users behind firewall-heavy setups or in environments with aggressive content filtering (such as corporate networks or regions with heavy censorship), protocols like DoH have a distinct advantage because they seamlessly integrate with standard HTTPS traffic. The port 443 used by DoH is commonly open in nearly every network environment, making it a robust choice.

Conversely, networks that impose strict rules on non-standard ports can easily detect and block DoT traffic since it relies on TCP port 853. This makes DoT's performance more sensitive to network policies, and in such cases, users may experience degraded service.

Device and Client Support

The implementation quality on client devices is another critical factor. DoH benefits from being integrated into modern operating systems and browsers with established HTTPS libraries, which contribute to its overall stability and ease of deployment. The seamless fallback mechanisms in some clients further enhance its robustness—if one protocol encounters issues, alternatives may be employed without disrupting service.

Although DoT is fundamentally sound and well-established in many environments, its dedicated port dependency means that any misconfiguration or blockage at the network level can severely affect performance. DoQ, while showing considerable promise in handling poor network conditions and packet loss, still requires wider client and server support to become a mainstream option.

Evolving Standards and Protocol Maturity

The evolution of protocols like HTTP/3, which builds on QUIC (and by extension DoQ), continues to reshape expectations in DNS resolution technology. DoH has seen significant maturity over the years, leveraging ongoing improvements in HTTPS performance. The security community continues to refine these protocols, addressing vulnerabilities and performance bottlenecks.

DoQ, being the latest entrant, is still under active development and optimization. Its advantages in handling congested networks and effectively managing multiple simultaneous connections are promising, but practical deployment is influenced by the pace of adoption and the consistency of its implementation across varying systems.

Practical Recommendations for NextDNS Users

Primary Recommendation: DoH

For most users, DoH remains the most pragmatic choice when configuring NextDNS. Its ability to piggyback on HTTPS traffic ensures that it remains operational in virtually all network environments, from secured corporate systems to public Wi-Fi networks. The mature implementation available on most modern devices minimizes potential hiccups with compatibility, and the established fallback mechanisms in DNS clients further increase its reliability.

Considering DoQ for Advanced Scenarios

Users who have modern devices and modern network infrastructure, along with a requirement for enhanced performance, should consider testing DoQ. This protocol’s design to handle packet loss and latency issues is particularly beneficial in environments where network reliability is a concern. While its support might not be as ubiquitous as DoH, early adopters may find that DoQ offers superior performance when network conditions are less than ideal. However, careful testing in your specific network environment is recommended, as real-world results may vary depending on the maturity of client implementations.

Situations Favoring DoT

DoT could be an optimal choice in environments where the network configuration is strictly controlled and where the risk of port-blocking is minimal. For users operating within private networks or regions where dedicated service configurations are managed carefully, DoT may deliver slightly faster response times due to lower protocol overhead under optimal conditions. However, any change in network policy or firewall configuration can lead to inconsistent performance, making it less ideal for general use.

Advanced Considerations

Security and Privacy Implications

All three protocols—DoH, DoT, and DoQ—provide significant improvements in the security of DNS resolutions by encrypting queries and responses, thus reducing the risk of eavesdropping and unauthorized manipulation. DoH and DoQ are particularly effective in disguising DNS traffic as regular HTTPS or UDP traffic, complicating efforts by adversaries and network monitors to filter or tamper with the data. While DoT also encrypts data, its reliance on a dedicated port means it is more recognizable, potentially making it a target in restrictive networks.

From a privacy perspective, the use of encrypted DNS queries helps to uphold user anonymity by preventing third parties from easily identifying browsing patterns. This is a crucial advantage in an era of increased surveillance and data tracking. NextDNS, with its support for these protocols, ensures that users have access to secure DNS resolution regardless of the protocol chosen.

Performance Under Adverse Conditions

In networks that are prone to packet loss or where congestion is common, DoQ’s design has a theoretical edge. The use of QUIC ensures that any lost packets are efficiently recovered, maintaining throughput and reducing the stress on the communication channel. While practical differences may be minimal in ideal circumstances, in degraded network conditions, DoQ could prove to be more resilient.

DoH, while slightly heavier on resource usage during initial connections, benefits from continuous optimization and widespread client support, making it a robust option even when network conditions are less than perfect. DoT retains its competitive performance in stable environments, but any issues with port accessibility can quickly undermine its potential advantages.

Conclusion

In summary, when configuring NextDNS, the choice between DoH, DoQ, and DoT depends largely on network conditions, device support, and specific performance needs. DoH stands out as the most reliable and widely compatible option, particularly for users operating in diverse network environments where firewall restrictions are a concern. Its ability to integrate with important HTTPS infrastructures makes it both secure and stable.

DoQ offers an exciting glimpse into the future with its promise of lower latency and improved performance in packet loss scenarios. However, given its current stage of adoption, it is best suited for advanced users with modern infrastructure who are willing to experiment for potential performance benefits.

Lastly, DoT remains a solid option in controlled, stable environments but may falter when exposed to networks employing strict port filtering. Users should assess their specific setup and requirements to determine the most effective protocol for optimal DNS resolution stability.

Overall, while each protocol has its merits, DoH emerges as the most balanced choice for most NextDNS users, thanks to its robust performance under a broad range of network conditions and its seamless integration with existing HTTPS infrastructures.