DNS 记录

搜索并了解 DNS 记录类型 — 示例、使用场景、RFC 参考

DNS 记录类型参考手册。每条记录包含描述、zone 文件语法示例及使用建议。

搜索

14 种记录类型

Address (IPv4)RFC 1035

Maps a hostname to a 32-bit IPv4 address.

示例

example.com.    300    IN  A    93.184.216.34

使用场景

Standard hostname → IPv4 mapping. Most websites have at least one A record.

AAAA

Address (IPv6)RFC 3596

Maps a hostname to a 128-bit IPv6 address.

示例

example.com.    300    IN  AAAA  2606:2800:220:1:248:1893:25c8:1946

使用场景

IPv6 endpoint resolution. Modern dual-stack deployments include both A and AAAA.

CNAME

Canonical NameRFC 1035

Alias of one hostname to another. The DNS lookup follows the alias.

示例

www.example.com.   300   IN  CNAME  example.com.

使用场景

Pointing subdomains (www, app) to a primary host. Cannot coexist with other records on the same name.

Mail ExchangeRFC 1035

Specifies mail servers for a domain, with a priority value.

示例

example.com.    300    IN  MX    10 mail.example.com.

使用场景

Required for receiving email. Lower priority = higher preference.

TXT

文本RFC 1035

Arbitrary text strings. Used for verification and policy declarations.

示例

example.com.    300    IN  TXT   "v=spf1 include:_spf.google.com ~all"

使用场景

SPF/DKIM/DMARC email auth, domain verification (Google/Facebook), public keys.

Name ServerRFC 1035

Delegates a DNS zone to authoritative name servers.

示例

example.com.    300    IN  NS    ns1.example.com.

使用场景

Required at the apex of every zone. Lists which servers answer queries for this domain.

SOA

Start of AuthorityRFC 1035

Authoritative info about the zone: primary NS, admin email, serial, timers.

示例

example.com.   3600   IN  SOA   ns1.example.com. admin.example.com. 2026050701 7200 3600 1209600 3600

使用场景

Exactly one per zone, at the apex. Required by DNS spec.

SRV

Service LocatorRFC 2782

Specifies the host/port for a service — protocol, weight, priority.

示例

_sip._tcp.example.com. 300 IN SRV 10 60 5060 sipserver.example.com.

使用场景

SIP/XMPP/LDAP/Minecraft service discovery. Format: _service._proto.name.

CAA

Certification Authority AuthorizationRFC 8659

Restricts which CAs can issue TLS certificates for the domain.

示例

example.com.   300    IN  CAA   0 issue "letsencrypt.org"

使用场景

Prevent unauthorized CAs from issuing certs for your domain. Recommended for security.

PTR

Pointer (Reverse DNS)RFC 1035

Maps an IP address back to a hostname (in in-addr.arpa or ip6.arpa).

示例

34.216.184.93.in-addr.arpa.  300  IN  PTR  example.com.

使用场景

Reverse DNS for email server reputation (spam filters), logging.

HTTPS

HTTPS Service BindingRFC 9460

Encrypted ALPN/SNI hints for HTTPS connections; supports ECH.

示例

example.com.   300    IN  HTTPS  1 . alpn="h3,h2"

使用场景

Modern HTTPS optimization (HTTP/3 hint, encrypted client hello). Browser support growing.

SVCB

Service BindingRFC 9460

Generic service binding (HTTPS is a specific subtype).

示例

_dns.example.com. 300 IN SVCB 1 dns.example.com. alpn="dot"

使用场景

Generic service alias with hints (e.g., DNS over TLS). Less common than HTTPS.

Delegation SignerRFC 4034

DNSSEC — fingerprint of child zone's KSK, stored in parent zone.

示例

example.com. 86400 IN DS 12345 13 2 ABC123...

使用场景

DNSSEC chain of trust. Required when a zone is DNSSEC-signed.

DNSKEY

DNS Public KeyRFC 4034

DNSSEC — public key for verifying signatures in the zone.

示例

example.com. 86400 IN DNSKEY 257 3 13 ABC456...

使用场景

DNSSEC verification. Stored at zone apex; signed by KSK referenced by parent's DS.

使用方法

Type a record type, keyword, or use case into the search field (e.g. "MX", "mail", "DNSSEC").
Browse the matching cards, each showing the record type badge, full name, RFC reference, description, a concrete example, and when to use it.
Leave the field empty to see all 14 record types at once.

示例

Searching "MX" shows the Mail Exchanger record, RFC 1035, with example "example.com. IN MX 10 mail.example.com." and explains it is used to route email for a domain.
Searching "DNSSEC" returns DS and RRSIG cards explaining how DNS responses are cryptographically signed.

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