What is DNS: explaining the domain name system and its role in network anonymity
The Hypertext Transfer Protocol (HTTP) and the World Wide Web could not function without another, equally critical system: the Domain Name System (DNS). DNS is a global, distributed database that acts as the “phone book” of the Internet, translating human-readable domain names (like proxyverity.com) into machine-readable IP addresses (like 192.0.2.44). Understanding DNS is vital, as every web request, before moving to HTTP, begins with a DNS query. For a proxy or VPN user, knowing the mechanisms of DNS is the key to ensuring complete anonymity and security.
The fundamental problem the DNS solves
Computers and other network devices communicate using IP addresses. These numerical addresses are efficient for routers but completely inconvenient for humans.
DNS solves this problem by providing:
- Human Accessibility: It is much easier for a user to remember google.com than 142.250.75.206.
- Flexibility and Portability: If a server’s IP address changes (e.g., due to migration to new hosting), the domain name remains the same. The administrator simply updates the DNS record, and the system continues to direct traffic to the new address without requiring user intervention.
The hierarchical and distributed structure of DNS
DNS is not a single centralized database. It is a distributed, multi-level system that ensures its scalability and fault tolerance. A domain name is read from right to left, where each level represents a separate zone managed by its own set of servers:
Root level
Denoted by the single dot (.) at the end of the fully qualified domain name. Root servers are 13 groups of logical servers worldwide (physically there are hundreds) that know where to find the TLD servers. They are the starting point for every external DNS query.
Top-level domains (tld)
This is the second level of the hierarchy (e.g., .com, .org, .ru, .net, or geographical ones like .uk, .de). TLD servers are managed by organizations like ICANN and know the location of the authoritative DNS servers for all domains registered under them.
Second-level domains
This is the name you register and purchase (e.g., proxyverity in proxyverity.com). Management of this level is delegated to the owner.
Subdomains and hostnames
- Subdomains: Additional labels created by the domain owner to organize content (e.g., blog or api in blog.proxyverity.com).
- Hostname: Defines a specific computer or resource (e.g., www).
The detailed DNS resolution process (the DNS lookup)
DNS Resolution is a multi-step process that occurs in milliseconds and involves the interaction of four key types of servers.
- Client Cache Check: The browser or operating system first checks its local cache. If the record is found and its TTL (Time-to-Live) has not expired, the process ends here.
- Recursive Query to the Resolver: If the cache is empty, the client sends a recursive query to a Recursive Resolver (usually your Internet Service Provider’s DNS server or a public service, such as Cloudflare 1.1.1.1).
- Iterative Queries (Resolver’s Work): The Recursive Resolver takes over all the work:
- It queries the Root Server (.). The Root Server responds with the address of the TLD Server (.com).
- It queries the TLD Server (.com). The TLD Server responds with the addresses of the Authoritative Servers for proxyverity.com.
- It queries the Authoritative Server for proxyverity.com. The Authoritative Server provides the final IP address.
- Caching and Response: The Resolver caches the received IP address for the duration specified in the TTL and sends it back to the client.
- Connection Establishment: The client, having received the IP address, can establish a TCP connection and begin the HTTP exchange with the server.
Advanced DNS record types (resource records)
DNS records are files stored on authoritative servers that contain information about a resource.
| Record Type | Purpose | Description |
|---|---|---|
| A (Address) | Domain -> IPv4 Address Mapping. | The primary record for websites. |
| AAAA (Quad-A) | Domain -> IPv6 Address Mapping. | The A-record equivalent for the new generation of IP. |
| CNAME (Canonical Name) | Creates a domain alias. | For example, blog.proxyverity.com can be an alias for proxyverity.hostingprovider.com. |
| MX (Mail Exchange) | Mail servers. | Defines where email for the domain should be delivered. |
| TXT (Text) | Arbitrary text. | Often used for domain verification, configuring SPF, DKIM, and DMARC to prevent spam and phishing. |
| NS (Name Server) | Authoritative servers. | Indicates which DNS servers are primary for this domain. |
| PTR (Pointer) | Reverse lookup. | Maps an IP address back to a domain name (used for reverse DNS lookups, often to verify mail server authenticity). |
| SRV (Service) | Service location. | Used to determine the location of services such as SIP telephony or XMPP messengers. |
The problem of DNS leaks and ensuring anonymity
For proxy and VPN users, DNS queries represent one of the most serious threats to anonymity.
What is a DNS leak?
When you use a VPN or proxy, the expectation is that all your traffic (including DNS queries) will be routed through the secured tunnel. A DNS Leak occurs when your DNS query is mistakenly or due to incorrect configuration sent to your Internet Service Provider’s (ISP) DNS server, bypassing the proxy/VPN.
Consequences for anonymity:
- Your ISP receives a complete log of all the websites you visit, even if the traffic itself (HTTP) is encrypted and passes through the VPN/proxy.
- This reveals your real geographical location and actual network activity.
How proxies handle DNS:
- Traditional Proxies (HTTP/SOCKS4): These proxies can perform the DNS lookup on their side, masking your real IP address. However, if the client (browser) is configured to use the proxy only for HTTP/S, it may ignore the proxy for DNS.
- SOCKS5 and VPN: These technologies typically intercept and tunnel all DNS queries, preventing leaks, as they operate at lower network layers.
Modern DNS evolution and security
Traditionally, DNS queries were sent as unencrypted UDP traffic. This created two main problems: vulnerability to spoofing and lack of confidentiality.
DNS security extensions (DNSsec)
- Principle: DNSSEC is a set of specifications that add cryptographic signatures to DNS records.
- How it works: When you query a record, DNSSEC allows the client to verify that the response came from the authoritative server and was not altered in transit by an attacker.
- What DNSSEC does not do: It does not encrypt the DNS query; it only confirms its integrity and authenticity.
Encrypting DNS traffic (doh and dot)
To address the issue of confidentiality and protection against interception, protocols that encrypt DNS traffic were developed:
| Protocol | Full Name | Transport Protocol | Advantages |
|---|---|---|---|
| DoT (DNS over TLS) | DNS over TLS | Port 853 (TLS) | Encrypts DNS queries using the same protocol as HTTPS. Makes monitoring and censorship more difficult. |
| DoH (DNS over HTTPS) | DNS over HTTPS | Port 443 (HTTP/TLS) | Encapsulates the DNS query within standard HTTPS traffic. Extremely effective for bypassing filters, as it looks like ordinary web traffic. |
Using DoH or DoT, especially in combination with a proxy or VPN, significantly enhances your confidentiality by hiding queries even from your Internet Service Provider.
DNS diagnostics and troubleshooting tools
For working with proxies and networks, it is important to be able to manually check DNS records.
| Tool | Purpose | Example Usage |
|---|---|---|
| nslookup | Simple diagnostic tool. | nslookup proxyverity.com |
| dig (Domain Information Groper) | Powerful and preferred tool. | dig proxyverity.com A |
| whois | Checks domain registration data. | whois proxyverity.com |
Using dig allows you to manually check exactly what IP address your proxy or server sees, which is critically important when debugging access or geo-blocking issues.
TTL (time-to-live) and its impact on speed and updates
TTL, or Time-to-Live, is a value (in seconds) attached to every DNS record.
- High TTL (24 hours): Good for very stable, rarely changing IP addresses. Reduces the number of DNS queries, lowering the load on the authoritative server and speeding up page loading for the user.
- Low TTL (5 minutes): Used when an IP address is expected to change soon (e.g., during server migration or load balancing). A low TTL ensures that new settings spread more quickly across the Internet.
- Critical Aspect for Proxies: If you are moving a domain to a new IP address (e.g., changing the target server for a reverse proxy), a low TTL ensures that proxy server caches globally quickly expire and begin using the new, correct IP.
Conclusion
The Domain Name System is the invisible but the very first and one of the most crucial steps in any network interaction. Its distributed and hierarchical structure ensures global reliability. However, for professionals working with proxies and anonymity, DNS represents a potential point of failure. Understanding DNS resolution mechanisms, actively using encryption (DoH/DoT), and being vigilant about DNS leaks are necessary conditions for ensuring complete network confidentiality.
