Every internet request starts with the domain name system (DNS). But, if DNS is the internet’s phonebook (or GPS, or post office—take your pick), how does it turn a human-friendly name like dnsmadeeasy.com into a machine-readable route to your destination? The answer is DNS.
DNS queries form the invisible handshake that happens when your device looks up a domain and gets back an IP address. But as simple as that sounds, the way this DNS traffic flows, and how it’s managed, is becoming more complex.
Whether you’re a network admin or just someone who wants a faster, safer online experience, understanding how this traffic works (and how to manage it) is more important than ever.
What is DNS Traffic?
Every time you visit a website, open an application, or do anything that uses a domain name, DNS queries handle the back-and-forth that routes your device to its destination. Users remember simple domain names, not long IP addresses, so when a user types a domain into their browser, the DNS query asks for the address and the response returns an IP address, e.g., 192.0.2.1. That exchange is DNS traffic in action.
Every day, there is a staggering volume of DNS queries. In June 2025, UltraDNS processed 136 billion DNS queries daily. Unfortunately, massive amounts of DNS traffic can lead to problems: services can become overloaded and crash, or users may see slower response times.
DNS traffic management is essential to ensuring the availability, reliability, and integrity of your organization’s digital infrastructure across different locations.
What is Encrypted DNS Traffic?
DNS was never designed with privacy and security in mind. By default, DNS queries are sent in plaintext, making traffic vulnerable to interception and tampering. That is where encryption comes into play.
There are two main DNS encryption protocols:
- DNS over HTTPS (DoH): routes DNS queries through the encrypted HTTPS protocol used for secure web browsing.
- DNS over TLS (DoT): uses (Transport Layer Security (TLS) to encrypt queries.
While both protocols encrypt DNS queries, they differ in transport mechanisms and operational behavior. DoH uses HTTPS over port 443, allowing DNS traffic to blend with regular web traffic. In direct contrast, DoT operates on a dedicated port (853), which can simplify network management but also makes it easier to identify and potentially block DoT traffic. There are also differences in deployment. While DoH is increasingly integrated into modern browsers for a user-friendly option, DoT is often implemented at the operating system or network level.
While encrypted DNS traffic helps bolster security and privacy, there are pros and cons to consider.
Pros
- User privacy: Because traditional DNS queries are sent in plaintext, they are visible to third parties such as Internet Service Providers (ISPs), advertisers, and malicious entities. Encrypted DNS traffic helps prevent unauthorized monitoring and strengthens privacy.
- Security: Encrypted traffic is harder to intercept and alter. This helps prevent the risk of DNS-based attacks like DNS spoofing or man-in-the-middle (MitM).
Cons
- Compatibility Issues with Legacy Systems: Older network monitoring tools, firewalls, and appliances may not support encrypted DNS without updates or reconfiguration.
- Implementation Complexity: Rolling out DoH requires careful planning to ensure traffic is routed to trusted internal resolvers, not random external ones.
- Potential Performance Overhead: Encrypting DNS increases payload size, which may lead to higher latency or slower page load times, especially under heavy network load.
What Does Blocking DNS Traffic Mean?
Blocking DNS traffic refers to intentionally preventing certain types of DNS queries from reaching their destination. Organizations can enforce policies to block both unencrypted and encrypted DNS traffic. This can occur for a variety of reasons, each with different implications:
- Network Policies: Some organizations may block access to specific domains to enforce acceptable use policies, such as restricting social media, adult content, or gaming sites.
- Security Controls: Because encrypted protocols can create challenges for network administrators, some organizations may block encrypted traffic to allow administrators to inspect DNS traffic, preventing malicious activity and blocking potential cyberattacks.
- Technical Limitations: Older network infrastructure may not support encrypted DNS, leading to blocked queries due to incompatibility with legacy systems or firewalls.
- Routing Strategies: Certain networks may block encrypted DNS traffic to redirect DNS queries for ad manipulation or traffic flow
- Traffic Steering and Manipulation: Some ISPs or networks block encrypted DNS to maintain control over DNS resolution, often for purposes like ad injection, traffic shaping, or content filtering.
- Misconfiguration: Sometimes, blocking is unintentional. Incorrect firewall rules, misconfigured DNS server settings, or network configurations can cause failed lookups and broken connectivity.
How Does DNS Blocking Work?
DNS blocking typically happens at the resolver or network level, where policies are enforced to deny resolution of certain domains or entire categories of traffic. Here are some of the most common methods used for DNS blocking:
- DNS Filtering: DNS resolvers return a false or null response (NXDOMAIN) when users try to access blocked domains.
- Firewall Rules: Network firewalls can block outbound DNS queries to specific IPs, ports, or external DNS servers, especially those using encrypted protocols like DoH (port 443) or DoT (port 853).
- Deep Packet Inspection (DPI): Some advanced networks analyze DNS traffic patterns or signatures, even if encrypted, to detect and block unwanted queries.
Encrypted DNS traffic can make blocking more challenging, as it obscures both the domain being queried and the destination server. This makes it difficult for network administrators to apply traditional DNS filtering or inspection. As a result, some organizations choose to block encrypted DNS traffic altogether.
Why Would a Network Block Encrypted DNS Traffic?
Despite the benefits of encryption, some networks block encrypted DNS traffic. This is common in environments like offices, schools, or public Wi-Fi networks; even your local café may restrict it. There are several practical and strategic reasons why a network might block encrypted DNS protocols like DoH and DoT:
Security Monitoring
Normally, network administrators inspect DNS queries in transit to block access to malicious or unauthorized domains. However, encryption prevents this inspection, making it harder to detect threats like malware communications, data exfiltration, or DNS tunneling. As a result, some organizations block encrypted DNS traffic to restore visibility and maintain security controls.
Compliance Requirements
Regulated industries, like healthcare, finance, and government, must maintain audit logs and full visibility into network traffic. Encrypted DNS can interfere with these requirements by obscuring DNS queries, which may complicate compliance, monitoring, and incident response.
Performance and Stability Concerns
Encrypted DNS can affect network performance, as encrypted queries typically have larger payload sizes than traditional plaintext DNS. This added overhead may slow communication with DNS resolvers, potentially increasing latency when loading web pages. On constrained or legacy networks, the extra processing required for encryption can introduce noticeable delays or overwhelm devices that aren’t designed to handle secure DNS protocols efficiently.
Centralized Control
Blocking encrypted DNS ensures users cannot connect to third-party resolvers that might circumvent internal DNS rules, helping retain control over data routing and security enforcement.
5 Best Practices for Managing DNS Traffic
DNS responses must be performant to deliver an optimized, enhanced user experience. DNS traffic management is used to improve performance, speed, and ensure availability. Below is a non-exhaustive list of best practices that can help optimize performance and support network resilience.
1. Properly Configure DNS Settings
Any good security management strategy begins with a foundational setup. For DNS, this means ensuring servers are properly configured to handle requests efficiently, as misconfigurations can result in inadvertently blocking traffic. Routinely verify resolver settings, adjust time-to-live (TTL) values as needed, and apply updates to stay aligned with performance and security standards.
2. Monitor DNS Traffic
Regularly monitor DNS logs to identify unusual query patterns, traffic spikes, or attempts to contact known malicious domains. Proactive monitoring can help detect threats like DNS tunneling, spoofing, or unauthorized access.
3. Implement DNS Caching
Enable caching at the client, application, or resolver level to speed up domain resolution and reduce lookup delays. Organizations that use an authoritative DNS provider should configure their TTL values to help resolvers cache responses efficiently, minimizing redundant queries, easing load on authoritative servers, and improving overall performance and scalability.
4. Utilize DNS Lookup Tools
Leverage tools like dig, nslookup, or browser-based DNS checkers to troubleshoot resolution issues. Dig is especially helpful for inspecting specific record types, tracing DNS paths, and identifying issues like propagation delays, misconfigurations, or missing records; all without the noise of unrelated data.
5. Implement DNS Load Balancing
Finally, but perhaps most importantly, implement DNS load balancing. DNS load balancing is a traffic management technique that distributes incoming DNS queries across multiple servers or endpoints to improve performance, increase fault tolerance, and maintain high availability. There are several common methods for DNS load balancing:
- Round Robin: Distributes DNS responses in a rotating sequence. Each query receives a different server IP from a predefined list, spreading traffic evenly.
- Geolocation-Based Routing: Routes users to the server nearest to their physical location, reducing latency and improving response times, especially for globally distributed services.
- Weighted Load Balancing: Assigns traffic proportionally based on server capacity or performance. Higher-capacity servers receive more queries, enabling smarter resource utilization.
- Failover-Based Routing: Provides redundancy by directing traffic to a backup server if the primary becomes unavailable, ensuring service continuity during outages or maintenance.
Ready to Take Control of Your DNS Traffic?
You want to provide your users with a performant, seamless online experience, and that starts with smart DNS traffic management.. DNS Made Easy has a robust, global network that routes queries to the closest and fastest point of presence. Our built-in traffic steering features help distribute DNS traffic intelligently, enhancing the performance, uptime, and reliability of your digital infrastructure.
Explore how DNS Made Easy can streamline your DNS traffic management.