DNS Server

  • Fabian Sinner
  • November 6, 2023

Table of content

    DNS Server

    A DNS server (Domain Name System server) is an important part of the Internet that serves to convert human-friendly domain names into the corresponding IP addresses used by computers and networks to identify and communicate with each other.

    The DNS server plays a crucial role by resolving domain name requests from users or systems into the corresponding IP addresses. This facilitates Internet navigation by allowing users to access Web sites using domain names they are familiar with without having to know the underlying complex IP addresses. The DNS server thus enables basic communication and access to various online resources.

    How does the resolution of a DNS server work?

    The DNS resolution process takes place in several steps:

    1. The user enters a domain name into their web browser, e.g. www.example.com.
    2. The web browser sends a DNS query to a DNS resolver to obtain the IP address for the entered domain name. The DNS resolver is often provided by Internet service providers.
    3. The DNS resolver forwards the query to one or more DNS root servers. These servers are the top level of the DNS hierarchy and point to the top-level domains (TLDs), such as .com, .org, or .net.
    4. The DNS root server refers the resolver to the responsible TLD name server for the requested domain (for example, .com).
    5. The TLD name server points the resolver to the authoritative name server for the requested domain (for example, the servers of example.com).
    6. The authoritative name server returns the IP address for the requested domain name.
    7. The DNS resolver stores the obtained IP address and returns it to the web browser.
    8. The web browser uses the obtained IP address to connect to the corresponding web page.

    DNS resolution is important because it is the basis for identifying and communicating resources on the Internet. Without DNS resolution, we would be forced to enter IP addresses directly, which would make using the Internet much more difficult.

    What are the types of DNS servers?

    There are different types of DNS servers, each of which performs different tasks in the Domain Name System. The DNS root servers form the top level of the DNS hierarchy and are responsible for forwarding queries to the top-level domain name servers (TLD name servers). There are a total of 13 root servers worldwide. The TLD name servers are specifically responsible for managing top-level domains such as .com, .org and .net. They refer to the authoritative name servers that manage the second-level domains below their TLD.

    The authoritative name servers are responsible for a particular domain and contain information about the associated IP addresses. Caching resolvers serve as temporary caches and speed up the resolution of frequently requested domains. These resolvers are often set up by Internet service providers.

    Forwarding resolvers forward DNS requests to other resolvers or DNS servers to improve the speed or optimization of resolution. Recursive resolvers, on the other hand, handle the entire resolution process of a requested domain by contacting the necessary name servers and compiling the information they receive.

    Finally, there are slave name servers that mirror data from authoritative name servers and thus act as backup servers to ensure availability and redundancy of DNS data.

    The different types of DNS servers work together to ensure the smooth functioning of the Domain Name System and that domain names can be successfully resolved into their associated IP addresses.

    Are there ways to bypass the censorship or blocking of a DNS server?

    There are several ways to successfully bypass DNS-based censorship or blocking. One popular option is to use alternative DNS servers. Instead of the default DNS servers of the Internet service provider, public DNS resolvers such as Google DNS (8.8.8.8, 8.8.4.4) or Cloudflare DNS (1.1.1.1, 1.0.0.1) can be used here. These DNS servers can bypass DNS blocks, as they are usually not subject to the same restrictions.

    Another option is the VPN (Virtual Private Network). A VPN encrypts Internet traffic and redirects it through servers in different countries. DNS blockades can be circumvented using VPN, since DNS servers that are not affected by censorship measures are accessed.

    DNS-over-HTTPS (DoH) and DNS-over-TLS (DoT) technologies allow DNS queries to be encrypted, making censorship measures or blockades more difficult to implement.

    The Tor network can circumvent DNS blocking by routing Internet traffic through a variety of servers around the world to disguise the user’s identity and location.

    Proxy servers, on the other hand, can route DNS requests through their own DNS servers to bypass blockades. However, some proxy servers may also be censored.

    It is important to note that circumventing DNS censorship may have different legal and ethical aspects depending on the country and region. When using such methods, you should make sure that you understand and follow the applicable laws and guidelines.

    How can I ensure that my DNS queries are private and secure, especially on public WLAN networks?

    To ensure that your DNS requests are private and secure, there are several measures you should ideally follow. One is to use encrypted DNS protocols such as DNS-over-HTTPS (DoH) or DNS-over-TLS (DoT). These protocols encrypt your DNS requests to ensure that they cannot be intercepted or tampered with by third parties.

    In addition, you should choose trusted and secure DNS resolvers. Public DNS resolvers such as Google DNS (8.8.8.8, 8.8.4.4) or Cloudflare DNS (1.1.1.1, 1.0.0.1) support these encrypted protocols and provide additional protection for your DNS queries.

    Using a virtual private network (VPN) is also recommended. A VPN encrypts all your Internet traffic, including your DNS queries, and thus protects your privacy when you are on public WLAN networks.

    To further minimize risk, it’s best to avoid insecure WLAN networks and use only trusted and secure connections. Also, keep your devices and software up to date to benefit from security updates. Firewall and antivirus software also serve as additional security measures.

    By following these tips and making careful decisions on public Wi-Fi networks, you can ensure that your DNS requests remain private and secure.

    Are there special DNS services with increased security?

    Yes, you can use special DNS services that have an additional security barrier built in besides the usual functionality. One such service would be Link11’s Secure DNS. If you have any questions, feel free to contact one of our security experts.

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