Is DNS over HTTPS (DoH) Faster? A Deep Dive into Performance and Security

The question of whether DNS over HTTPS (DoH) is faster than traditional DNS is complex and doesn't have a simple yes or no answer. Performance depends on several factors, and the impact can vary significantly depending on your specific network conditions, location, and the DoH provider you use.

Factors Affecting DoH Speed

Several factors influence the perceived speed of DoH:

• Network Latency: The distance between your device and the DoH server plays a crucial role. A geographically closer server will generally lead to faster response times compared to a distant one. Traditional DNS also suffers from latency, but the impact can be different depending on the caching mechanisms in place.
• Server Load: If the DoH server is overloaded with requests, it will naturally be slower to respond. Similarly, a heavily loaded traditional DNS server will also exhibit slower response times.
• TLS Handshake Overhead: DoH uses HTTPS, which requires a TLS (Transport Layer Security) handshake before the DNS query can be sent. This handshake adds overhead, potentially slowing down the initial request. However, this overhead is often negligible for subsequent requests as the connection is reused.
• Caching: Both DoH and traditional DNS utilize caching. Efficient caching can significantly improve performance for frequently accessed domains. The effectiveness of caching depends on the implementation and configuration of both the client and server.
• Network Congestion: Congestion on your network can impact both DoH and traditional DNS. A slow internet connection will negatively affect both, regardless of the DNS protocol used.
• DoH Provider Choice: Different DoH providers have varying infrastructure and performance characteristics. Choosing a reputable provider with a well-optimized network infrastructure is essential for optimal speed.

DoH's Potential Speed Advantages

While the TLS handshake adds overhead, DoH can offer several advantages that indirectly improve speed or overall experience:

• Reduced Network Latency (in certain cases): If the DoH server is closer or better connected than your ISP's DNS servers, it can lead to faster resolution times.
• Improved Privacy and Security: DoH encrypts your DNS queries, protecting your browsing activity from eavesdropping. While not directly affecting speed, this enhanced privacy can lead to a smoother browsing experience by avoiding potential interference from network monitoring or manipulation.
• Potential for Better Caching: A well-designed DoH implementation could theoretically provide better caching compared to traditional DNS, especially when dealing with less frequently accessed domains.

When DoH Might Be Slower

In some scenarios, DoH might be slower than traditional DNS:

• Distance to the DoH server: If you're using a DoH server located far away, the increased latency will negatively impact performance.
• Overloaded DoH server: A highly loaded DoH server will result in slower response times.
• Poor network conditions: A slow internet connection will affect both DoH and traditional DNS, making any speed differences negligible.

Conclusion

Determining whether DoH is faster than traditional DNS requires careful consideration of several factors. In some cases, especially with a well-chosen provider and favorable network conditions, DoH might offer comparable or even slightly faster speeds. However, it's not guaranteed to be faster in all scenarios. The benefits of DoH often extend beyond speed to encompass enhanced privacy and security. The overall impact on your browsing experience depends on your specific circumstances and the quality of your internet connection and DoH provider. Consider these factors and conduct your own testing to determine if DoH offers a performance advantage in your unique situation.