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DNS Record Types Explained

The DNS record types that carry addresses, aliases, mail routing, verification text, and service discovery, each with a real wire value.

Every zone mixes a handful of record types to route traffic, mail, and verification. Each row gives the type's job and a real wire value to copy. Dig a name with these in mind and the answer reads like a config file.

Reference table · 22 entries
22 of 22 rows
Address
AMaps a name to one IPv4 address.example.com. 300 IN A 203.0.113.10
AAAAMaps a name to one IPv6 address.example.com. 300 IN AAAA 2001:db8::10
A x NSeveral A records on one name hand out round-robin addresses.203.0.113.10 / 203.0.113.11
PTRMaps an address back to a name inside in-addr.arpa or ip6.arpa.10.113.0.203.in-addr.arpa. PTR host.example.com.
Alias & delegation
CNAMEPoints a name at another name; the resolver chases the target until it finds addresses.www.example.com. CNAME web-lb.example.net.
CNAME @ apexA CNAME may not coexist with other records, so the zone apex cannot use one.example.com. CNAME ext.example.net. (rejected)
ALIAS / ANAMEProvider-flattened apex alias that answers with A or AAAA records.example.com ALIAS ext-hub.example.net.
NSDelegates the zone, or a subzone, to its authoritative servers.example.com. NS ns1.example.com.
Mail
MXLists the mail exchangers for a name.example.com. MX 10 mail.example.com.
MX priorityLower numbers win; equal numbers split the load.10 mail1.example.com. / 20 mail2.example.com.
Null MXStates that a domain accepts no mail at all (RFC 7505).example.com. MX 0 .
SPFA TXT record listing the servers allowed to send mail for the domain."v=spf1 include:_spf.example.com -all"
DKIMPublishes the public key for one selector under _domainkey.sel1._domainkey TXT "v=DKIM1; k=rsa; p=MIIB…"
DMARCTells receivers what to do with mail that fails SPF or DKIM._dmarc TXT "v=DMARC1; p=reject; rua=mailto:agg@example.com"
Text & verification
TXTCarries arbitrary strings for protocols and humans.example.com. TXT "v=spf1 -all"
TXT chunkingEach string holds at most 255 octets; long values split into quoted chunks.( "MIIBIjANBg" "kqhkiG9w0BAQ" )
Site verificationProves domain control to a search engine or SaaS provider."google-site-verification=abc123def"
_acme-challengeHolds the DNS-01 token that lets a certificate authority issue._acme-challenge TXT "gfj9Xq3R2v"
Service & authority
SRVLocates a service's port, priority, and weight under _service._proto._sip._tcp SRV 10 5 5060 sip.example.com.
SOANames the primary server, the admin mailbox, the serial, and the timers.ns1 hostmaster 2026090401 7200 3600 1209600 300
CAARestricts which certificate authorities may issue for the domain.0 issue "letsencrypt.org"
CAA issuewildGoverns wildcard issuance separately from host names.0 issuewild ";"