---
title: "Email Encyclopedia: What is DNS and How Does it Relate to Email?"
draft: false
date: 2025-07-17
artist: Yuanshu
summary: "DNS (Domain Name System) is the internet's 'phone book'"
tags: ["Email Encyclopedia", "Alibaba Mail"]
keywords: ["Enterprise Email, Email Encyclopedia"]
description: "DNS (Domain Name System) is the internet's 'phone book', responsible for converting human-readable domain names (like example.com) into computer-recognizable IP addresses (like 192.0.2.1). Its core function is to resolve the 'mapping relationship between domain names and IP addresses', allowing users to access websites or services without having to memorize complex numbers."
---
DNS (Domain Name System) is the internet's "phone book," responsible for converting human-readable domain names (like example.com) into computer-recognizable IP addresses (like 192.0.2.1). Its core function is to resolve the "mapping relationship between domain names and IP addresses," allowing users to access websites or services without having to memorize complex numbers.
## How DNS Works
When you enter a domain name in your browser, DNS completes the resolution through multi-layered server collaboration:
Local query: The browser first checks its own cache and the operating system's hosts file for records.
Recursive resolver (such as DNS servers provided by ISPs): If there's no local record, it initiates a request to the root domain server, which returns the address of the top-level domain (such as .com).
TLD servers (Top-Level Domain servers): Guide the resolver to find the authoritative domain name server that manages the domain (such as servers provided by domain registrars like Cloudflare).
Authoritative servers: Finally return the IP address corresponding to the domain name or other resource records (such as mail server addresses).
The entire process relies on distributed architecture and caching mechanisms: servers at each level temporarily store query results to accelerate subsequent requests and reduce load.
## Why Do We Need DNS?
Convenience: Domain names like baidu.com are easier to remember than IP addresses like 36.152.44.95.
Flexibility: When IP addresses change, only DNS records need to be updated, and users can still access through the original domain name.
Extended functionality: Beyond IP resolution, DNS also supports advanced uses such as load balancing (distributing traffic across multiple servers).
## Why Do Enterprise Email Systems Need to Configure DNS?
Enterprise email (like name@yourcompany.com) sending and receiving functions heavily rely on DNS MX records and security records. If not correctly configured, emails may not be delivered or may be marked as spam:
**1. MX Records (Mail Exchange Records)**
Function: Inform global mail servers "where to deliver emails sent to @yourcompany.com".
Configuration example:
yourcompany.com MX Priority:10 Mail Server: mail.yourcompany.com
Without MX records, external emails cannot find the target server, resulting in lost emails.
**2. Anti-spam Security Records**
SPF Records: Declare which servers are allowed to send emails on behalf of your domain, preventing others from forging your domain name.
DKIM Records: Add digital signatures to emails, verifying that email content has not been tampered with.
DMARC Records: Define handling policies (such as rejection or flagging) when emails fail SPF/DKIM verification.
Consequences of not configuring: Enterprise emails may be blocked as "spam" by recipient mailbox systems, or even exploited by hackers for phishing attacks.
**3. CNAME Records (Optional)**
Used to simplify mailbox login addresses, for example, directing mail.yourcompany.com to the email service provider's official portal (such as outlook.office.com), enhancing user experience.
## Summary of Configuration Importance
Ensure email deliverability: MX records are signposts guiding email delivery; without them, emails get "lost."
Maintain reputation and security: SPF/DKIM/DMARC records are the "identity cards" of enterprise emails; without them, emails are easily misjudged as spam or fraudulent.
Enhance professionalism: Unified enterprise domain emails (like name@company.com) appear more trustworthy than personal emails (like @gmail.com).
## Conclusion
DNS is the underlying hub of the internet, and enterprise email configuration is one of its advanced application scenarios. Correctly setting up MX and security records not only ensures smooth communication but also protects enterprise information security and brand image. For businesses, this is not just a technical requirement but also fundamental infrastructure for business operations.
