In website construction and maintenance, DNS record types are an unavoidable topic. Many novice website owners, when configuring a domain name for the first time, often simply follow tutorials, "fill in an IP address, click save," and once the website is accessible, they don't delve into the underlying principles. Later, when it comes to server migration, CDN acceleration, email configuration, or multi-service deployment, they find themselves almost completely ignorant of DNS record types, feeling uncertain during configuration and unsure where to troubleshoot problems. In reality, DNS records are not complex. Understanding the function and use cases of each record allows for proficiency in practical applications.

　　Before discussing specific record types, let's briefly understand what DNS does. The core function of DNS is to translate "domain names" into "IP addresses." Humans are more likely to remember domain names, while computers can only recognize IP addresses for communication. The DNS system is like a distributed phone book; when a user accesses a domain name, DNS tells the browser "where the server corresponding to this domain name is located." DNS records are the specific entries in this phone book.

　　Different business needs require DNS to return different types of information, hence the various DNS record types. Not all records are used, but understanding their purpose will help you choose the right one when needed.

　　The most common, and often the first one beginners encounter, is the A record. The A record's function is very simple: it points a domain name to an IPv4 address. For example, pointing www.example.com to 1.2.3.4. When a user accesses this domain, the DNS returns this IP address, and the browser then connects to the corresponding server. Almost all basic website access is accomplished through A records. For small websites with only one server and no complex architecture, the A record is the most direct and stable choice.

　　Similar to the A record is the AAAA record, which points a domain name to an IPv6 address. With the gradual rollout of IPv6, more and more cloud service providers are beginning to support IPv6 access. If your server supports both IPv4 and IPv6, you can configure both A and AAAA records to ensure smooth access for users in different network environments. However, in practice, many novice website owners won't need AAAA records yet, but it's still important to know their existence and purpose.

　　The second very common type of record is the CNAME record. CNAME stands for "alias record," and it doesn't directly point to an IP address, but rather to another domain name. For example, pointing blog.example.com to example.cdnprovider.com will ultimately result in the DNS record following the pointed-to domain. The advantage of this method is its flexibility; when the target domain's IP address changes, the website owner doesn't need to modify their DNS records, making it suitable for CDN, cloud storage, load balancing, and other scenarios.

　　However, CNAME records also have significant limitations. Typically, root domains cannot use CNAME records, as this will affect the normal resolution of other records. Furthermore, CNAME records cannot coexist with certain record types, a common pitfall for beginners. Therefore, in scenarios requiring high compatibility, many cloud providers recommend using A records for root domains and CNAME records for subdomains.

　　Next is the MX record, which is closely related to email systems. The MX record specifies the server address responsible for receiving emails. When someone sends an email to @example.com, the email system first queries the MX record to see which server the email should be delivered to. If the MX record is not configured correctly, the mailbox will not be able to send or receive emails properly. For websites requiring corporate email or self-hosted mail servers, MX records are essential.

　　MX records typically have a "priority" concept. When multiple MX records are configured, the email system will first try the server with the higher priority (lower value). If that fails, it will try a backup server. This mechanism improves the reliability of the email system and is a detail that many beginners often overlook.

　　Besides MX records, email systems also frequently use TXT records. Originally used to store text information, TXT records have now become a "universal record" in verification and security configuration. Common SPF, DKIM, and DMARC email anti-counterfeiting mechanisms almost all rely on TXT records for configuration. Furthermore, many cloud services and third-party platforms require a TXT record when binding a domain name to verify domain ownership.

　　From a user experience perspective, TXT records themselves do not affect website access, but they play a crucial role in email delivery rates and domain security. If corporate emails frequently go to the spam folder, or domain binding services fail verification, the problem often lies with the TXT records.

　　Now let's look at NS records. NS records specify which group of DNS servers should resolve a given domain name. Novice website owners rarely need to manually modify NS records, as they are usually configured by default at the domain registrar. However, when changing DNS providers, using self-hosted DNS, or advanced cloud DNS services, it's essential to switch via NS records. Incorrect NS configuration can render the entire domain unresolved, a highly impactful operation.

　　Related to NS records are SOA records, the "Start of Authority Record" in the DNS zone. These records primarily identify management information for domain name resolution, such as the primary DNS server and refresh time. SOA records are typically maintained automatically by the DNS system and are rarely encountered by beginners, but they are a crucial foundation for the proper functioning of the entire resolution system.

　　In some special scenarios, SRV records may also be used. SRV records specify which server and port a service runs on, commonly found in instant messaging, voice services, or certain internal enterprise systems. SRV records are not common for ordinary websites, but they may be used when specific protocols or automated service discovery are involved.

　　Finally, there are some less commonly used but still worthwhile record types to understand, such as PTR records, primarily used for reverse DNS lookup, mapping IP addresses back to domain names, commonly seen in mail server anti-spam verification; and CAA records, used to specify which certificate authorities can issue SSL certificates for the domain, increasingly valued for improving HTTPS security.

　　After understanding these record types, the key question becomes: how should you choose in practice?

　　If you're just building a regular website, the simplest and safest way is to use A records to directly point the domain name to the server IP. If you need to access CDN or cloud acceleration services, then use CNAME records for subdomains, and A records or special resolution methods for the root domain, as recommended by your service provider. Whenever email is involved, you must carefully configure MX and related TXT records; otherwise, email problems will be very frequent. As for NS, SOA, and CAA records, unless you clearly understand what you're doing, it's not recommended to modify them arbitrarily.

　　In general, DNS record types are not "the more the better," but rather "use the right ones." Each record exists to solve a specific problem. For novice website owners, understanding the function and applicable scenarios of each record is more important than memorizing configuration steps. Once you have a solid foundation, everything else, from expanding business and optimizing architecture to troubleshooting, will be much easier.