DNS Record Types Reference

Record Type	Full Name	Purpose
A	Address Record	Maps hostname to IPv4 address
AAAA	IPv6 Address Record	Maps hostname to IPv6 address
CAA	Certificate Authority Authorization Record	Controls which CAs can issue certificates
CNAME	Canonical Name Record	Hostname alias pointing to another name
MX	Mail Exchange Record	Routes email to mail servers
NS	Name Server	Delegates a subdomain to other nameservers
PTR	Pointer Record	Reverse DNS — maps IP to hostname
SOA	Start Of Authority	Zone authority metadata (auto-managed)
SPF	Sender Policy Framework	Email sender validation policy
SRV	Service Locator	Service discovery with host, port, priority
SSHFP	SSH Public Key Fingerprint	Publishes SSH host key fingerprints
TXT	Text Record	Arbitrary text data

A — Address Record

Maps a hostname to one or more IPv4 addresses. The most common record type.

Field	Value
Format	IPv4 address
Example	`192.168.1.1`
Validation	Must be a valid IPv4 address
Multiple values	Supported — creates round-robin distribution

Dashboard
CLI

Select type A, enter the FQDN (e.g., www.example.com.), and add one or more IPv4 addresses in the Records field.

Create A record with multiple values

openstack recordset create \
  --type A \
  --record 192.168.1.10 \
  --record 192.168.1.11 \
  --ttl 3600 \
  example.com. www

Multiple A records for the same name create DNS round-robin distribution — each resolver query cycles through the values. This is not a replacement for a proper load balancer but useful for simple traffic spreading.

AAAA — IPv6 Address Record

Maps a hostname to an IPv6 address. Identical to A records but uses IPv6 notation.

Field	Value
Format	Full or abbreviated IPv6 address
Example	`2001:db8:3333:4444:5555:6666:7777:8888`
Validation	Must be a valid IPv6 address

Dashboard
CLI

Select type AAAA and enter one or more IPv6 addresses in the Records field.

Create AAAA record

openstack recordset create \
  --type AAAA \
  --record 2001:db8::1 \
  --ttl 3600 \
  example.com. www

CAA — Certificate Authority Authorization

Restricts which Certificate Authorities can issue TLS certificates for the domain. Supported by major CAs to prevent unauthorized certificate issuance.

Field	Value
Format	`<flags> <tag> "<value>"`
Example	`0 iodef mailto:security@example.com`

Flags: 0 = non-critical (CA may issue even if tag is unknown), 128 = critical (CA must not issue if tag is unknown)Tags:

Tag	Purpose
`issue`	Authorizes a CA to issue certificates for this domain
`issuewild`	Authorizes a CA to issue wildcard certificates
`iodef`	Reporting URI for policy violations (e.g., `mailto:security@example.com`)

Dashboard
CLI

Select type CAA and enter the flag, tag, and value in the Records field (e.g., 0 issue "letsencrypt.org").

Allow only Let's Encrypt

openstack recordset create \
  --type CAA \
  --record '0 issue "letsencrypt.org"' \
  --record '0 iodef "mailto:security@example.com"' \
  example.com. @

CNAME — Canonical Name (Alias)

Creates an alias that points one hostname to another. The target must resolve to an A or AAAA record.

Field	Value
Format	Fully qualified domain name
Example	`other-example.com`
Name example	`first.example.com.`

CNAME records cannot coexist with other record types at the same name, and cannot be created at the zone apex (@). Use an A record for the root domain hostname.

Dashboard
CLI

Select type CNAME and enter the target FQDN in the Records field.

Create CNAME record

openstack recordset create \
  --type CNAME \
  --record app.example.com. \
  example.com. api

MX — Mail Exchange

Specifies the mail servers responsible for receiving email for the domain. Multiple MX records with different priorities enable failover.

Field	Value
Format	`<priority> <hostname>`
Example	`10 mail.example.com`

Lower priority numbers have higher precedence. If the primary fails, resolvers try the next lowest priority.

Dashboard
CLI

Select type MX and enter each record as priority hostname. (e.g., 10 mail.example.com.).

Create MX records with primary and backup

openstack recordset create \
  --type MX \
  --record "10 mail.example.com." \
  --record "20 mail-backup.example.com." \
  example.com. @

NS — Name Server

Delegates a subdomain to a different set of nameservers. Zone apex NS records are auto-managed — do not modify them manually.

Field	Value
Format	Nameserver FQDN
Example	`ns1.example.com`

Dashboard
CLI

Select type NS and enter nameserver FQDNs in the Records field.

Delegate a subdomain

openstack recordset create \
  --type NS \
  --record "ns1.partner.com." \
  --record "ns2.partner.com." \
  example.com. sub

PTR — Pointer Record (Reverse DNS)

Maps an IP address back to a hostname. PTR records live in reverse zones (in-addr.arpa. for IPv4, ip6.arpa. for IPv6).

Field	Value
Format	Reverse FQDN
Example	`1.1.0.192.in-addr.arpa.`

For floating IP reverse DNS, use the dedicated Reverse DNS interface at Network > DNS Reverse instead of creating PTR records manually. See Reverse DNS.

SOA — Start Of Authority

Defines zone authority parameters. SOA records are auto-managed by the DNS service — you typically do not create or modify them directly.

Field	Value
Format	`<primary-ns> <admin-email> <serial> <refresh> <retry> <expire> <minimum>`
Example	`ns1.example.com admin.example.com 2013022001 86400 7200 604800 300`

Component	Description
Primary NS	Primary nameserver for the zone
Admin email	Contact email (with `.` instead of `@`)
Serial	Version number, incremented on each change
Refresh	Seconds between slave refresh checks
Retry	Seconds between retry after failed refresh
Expire	Seconds before slave stops serving stale data
Minimum	Negative caching TTL

SPF — Sender Policy Framework

Defines which mail servers are authorized to send email for the domain. Helps prevent email spoofing.

Field	Value
Format	SPF policy string
Example	`"v=spf1 ipv4=192.1.1.1 include:examplesender.email ~all"`

Dashboard
CLI

Select type SPF and enter the SPF policy string in the Records field.

Create SPF record

openstack recordset create \
  --type SPF \
  --record '"v=spf1 include:_spf.example.com ~all"' \
  example.com. @

Modern practice is to publish SPF data as a TXT record rather than the dedicated SPF type. Most mail systems check TXT records for SPF. Consider creating both for maximum compatibility.

SRV — Service Locator

Specifies the host and port for a specific service. Used by SIP, XMPP, LDAP, and other service-discovery protocols.

Field	Value
Format	`<priority> <weight> <port> <target>.`
Example	`10 0 5060 server1.example.com.`
Name format	`_service._protocol.example.com.` (e.g., `_sip._tcp.example.com.`)

Component	Description
Priority	Lower = higher priority (like MX)
Weight	Load balancing between same-priority targets (higher = more traffic)
Port	TCP/UDP port number for the service
Target	FQDN of the server hosting the service

Dashboard
CLI

Select type SRV. Enter the name as _service._protocol.domain. (e.g., _sip._tcp.example.com.) and the record as priority weight port target.

Create SIP SRV record

openstack recordset create \
  --type SRV \
  --record "10 20 5060 sip.example.com." \
  example.com. _sip._tcp

SSHFP — SSH Public Key Fingerprint

Publishes SSH host key fingerprints in DNS, allowing SSH clients to verify host keys via DNSSEC-secured lookups.

Field	Value
Format	`<algorithm> <fingerprint-type> <hex-fingerprint>`
Example	`4 2 123456789abcdef67890123456789abcdef67890123456789abcdef123456789`

Algorithm	Key Type
1	RSA
2	DSA
3	ECDSA
4	Ed25519
6	Ed448

Fingerprint Type	Hash
1	SHA-1
2	SHA-256

Dashboard
CLI

Select type SSHFP and enter the algorithm, fingerprint type, and hex fingerprint in the Records field.

Generate and create SSHFP record

# Generate fingerprints from host keys
ssh-keygen -r example.com -f /etc/ssh/ssh_host_ed25519_key.pub

# Create the record
openstack recordset create \
  --type SSHFP \
  --record "4 2 $(ssh-keygen -l -E sha256 -f /etc/ssh/ssh_host_ed25519_key.pub | awk '{print $2}' | cut -d: -f2- | tr -d ':')" \
  example.com. @

TXT — Text Record

Stores arbitrary text data. Widely used for domain ownership verification, SPF policies, DKIM keys, and DMARC.

Field	Value
Format	Any text string
Dashboard hint	(no format hint shown — enter any text value)

Dashboard
CLI

Select type TXT and enter the text value in the Records field.

openstack recordset create \
  --type TXT \
  --record '"v=spf1 include:_spf.example.com ~all"' \
  example.com. @

Manage Records

Create, update, and delete record sets using the Dashboard and CLI

Reverse DNS

Configure PTR records for your zone’s IP addresses

Create a Zone

Provision a new authoritative DNS zone

Troubleshooting

Resolve record conflicts and propagation issues

Core Services

Other Services

DNS Record Types Reference

Overview

Quick Reference

Record Type Details

Next Steps

Manage Records

Reverse DNS

Create a Zone

Troubleshooting

Core Services

Other Services

Documentation Index

​Overview

​Quick Reference

​Record Type Details

​Next Steps

Manage Records

Reverse DNS

Create a Zone

Troubleshooting

Overview

Quick Reference

Record Type Details

Next Steps