DoT and DoH refer to two protocols that secure Domain Name System (DNS) queries through encryption, ensuring user privacy and security. DoT stands for DNS over TLS and DoH stands for DNS over HTTPS. Both protocols aim to protect DNS queries from eavesdropping and tampering, but they differ in implementation, performance, and use cases.
DNS over TLS (DoT) is a protocol that encrypts DNS queries using Transport Layer Security (TLS) over a dedicated port, usually TCP port 853. This ensures that DNS lookups are secure and cannot be intercepted or manipulated by attackers. Since DoT uses a specific port, network administrators can more easily detect and manage encrypted DNS traffic.
DoT is ideal for environments where strict DNS control is required, such as enterprise networks, because administrators can monitor, allow, or block DNS traffic based on its dedicated port. However, its port-specific implementation makes it easier for firewalls or network filtering systems to block DoT traffic altogether.
One advantage of DoT is its efficiency. The protocol operates similarly to traditional DNS queries but adds encryption, reducing latency when compared to some other encrypted protocols. DoT is widely used in privacy-focused tools, such as Android 9 and later versions, which natively support DNS over TLS for secure DNS resolution.
DNS over HTTPS (DoH) encrypts DNS queries using the same protocol as web traffic—HTTPS—over TCP port 443. This makes DoH traffic indistinguishable from normal web traffic, significantly improving resistance to censorship or filtering by firewalls.
DoH is particularly favored for consumer privacy because it prevents ISPs, attackers, or intermediaries from monitoring DNS queries. Since DoH operates over a widely used port, blocking or filtering it without disrupting other web traffic becomes much more challenging.
Web browsers like Mozilla Firefox, Google Chrome, and Microsoft Edge have built-in support for DoH, allowing users to enable encrypted DNS resolution without relying on the operating system's DNS settings. Popular public DNS providers such as Cloudflare (1.1.1.1) and Google Public DNS (8.8.8.8) also support DoH.
A key challenge with DoH is its potential to bypass enterprise DNS controls. Since DoH queries are encrypted and blend with regular HTTPS traffic, network administrators may struggle to monitor or block unauthorized DNS lookups. This can pose security risks in managed environments that rely on DNS-based filtering and monitoring.
DoT and DoH both improve DNS security and privacy, but their differences influence their adoption and use cases:
Choosing between DoT and DoH depends on the use case:
- **For privacy and censorship resistance**: Use DoH because it is harder to block or filter. It is recommended for personal use and consumer environments. - **For enterprise and managed networks**: Use DoT for easier control, monitoring, and enforcement of DNS policies.
Both protocols offer significant security and privacy improvements over traditional DNS. Combining their strengths, organizations and users can enhance their overall internet security.
https://en.wikipedia.org/wiki/DNS_over_TLS