Supported Record Types
This chapter lists all record types PDNS supports, and how they are stored in backends. The list is mostly alphabetical but some types are grouped.
Warning: Host names and the MNAME of a SOA records are NEVER terminated with
a '.' in PowerDNS storage! If a trailing '.' is present it will inevitably cause
problems, problems that may be hard to debug. Use
to validate your zone data.
Note: Whenever the storage format is mentioned, this relates only to the way the record should be stored in one of the generic SQL backends. The other backends should use their native format.
The PowerDNS Recursor can serve and store all record types, regardless of whether these are explicitly supported.
The A record contains an IP address. It is stored as a decimal dotted quad string, for example: '203.0.113.210'.
The AAAA record contains an IPv6 address. An example: '2001:DB8:2000:bf0::1'.
A specialised record type for the 'Andrew Filesystem'. Stored as: '#subtype hostname', where subtype is a number.
Since 4.0.0, the ALIAS pseudo-record type is supported to provide CNAME-like mechanisms on a zone's apex. See the howto for information on how to configure PowerDNS to serve records synthesized from ALIAS records.
Specialised record type for storing certificates, defined in RFC 2538.
Since 4.0.0. The CDNSKEY (Child DNSKEY) type is supported.
Since 4.0.0. The CDS (Child DS) type is supported.
The CNAME record specifies the canonical name of a record. It is stored plainly. Like all other records, it is not terminated by a dot. A sample might be 'webserver-01.yourcompany.com'.
Hardware Info record, used to specify CPU and operating system. Stored with a single space separating these two, example: 'i386 Linux'.
The KEY record is fully supported. For its syntax, see RFC 2535.
The LOC record is fully supported. For its syntax, see RFC 1876.
A sample content would be:
51 56 0.123 N 5 54 0.000 E 4.00m 1.00m 10000.00m 10.00m
The MX record specifies a mail exchanger host for a domain. Each mail exchanger
also has a priority or preference. For example
10 mx.example.net. In the generic
SQL backends, the
10 should go in the 'priority field'.
Naming Authority Pointer, RFC 2915. Stored as follows:
'100 50 "s" "z3950+I2L+I2C" "" _z3950._tcp.gatech.edu'.
The fields are: order, preference, flags, service, regex, replacement. Note that the replacement is not enclosed in quotes, and should not be. The replacement may be omitted, in which case it is empty. See also RFC 2916 for how to use NAPTR for ENUM (E.164) purposes.
Nameserver record. Specifies nameservers for a domain. Stored plainly:
ns1.powerdns.com, as always without a terminating dot.
NSEC, NSEC3, NSEC3PARAM
Since 3.4.7. The OPENPGPKEY records, specified in RFC TBD, are used to bind OpenPGP certificates to email addresses.
Reverse pointer, used to specify the host name belonging to an IP or IPv6 address.
Name is stored plainly:
www.powerdns.com. As always, no terminating dot.
Responsible Person record, as described in RFC 1183.
Stored with a single space between the mailbox name and the more-information pointer.
peter.powerdns.com peter.people.powerdns.com, to indicate that
firstname.lastname@example.org is responsible and that more information about peter is
available by querying the TXT record of peter.people.powerdns.com.
The Start of Authority record is one of the most complex available. It specifies a lot about a domain: the name of the master nameserver ('the primary'), the hostmaster and a set of numbers indicating how the data in this domain expires and how often it needs to be checked. Further more, it contains a serial number which should rise on each change of the domain.
The stored format is:
primary hostmaster serial refresh retry expire default_ttl
Besides the primary and the hostmaster, all fields are numerical. PDNS has a set of default values:
- serial: 0
- refresh: 10800 (3 hours)
- retry: 3600 (1 hour)
- expire: 604800 (1 week)
- default_ttl: 3600 (1 hour)
The fields have complicated and sometimes controversial meanings. The 'serial' field is special. If left at 0, the default, PDNS will perform an internal list of the domain to determine highest change_date field of all records within the zone, and use that as the zone serial number. This means that the serial number is always raised when changes are made to the zone, as long as the change_date field is being set. Make sure to check whether your backend of choice supports Autoserial.
SPF records can be used to store Sender Policy Framework details (RFC 4408).
The SSHFP record type, used for storing Secure Shell (SSH) fingerprints, is
fully supported. A sample from RFC 4255 is:
2 1 123456789abcdef67890123456789abcdef67890.
SRV records can be used to encode the location and port of services on a domain
name. When encoding, the priority field is used to encode the priority. For example,
_ldap._tcp.dc._msdcs.conaxis.ch SRV 0 100 389 mars.conaxis.ch would be encoded
0 in the priority field and
100 389 mars.conaxis.ch in the content field.
Since 3.0. The TLSA records, specified in RFC 6698, are used to bind SSL/TLS certificate to named hosts and ports.
The TXT field can be used to attach textual data to a domain. Text is stored
plainly, PowerDNS understands content not enclosed in quotes. However, all quotes
") in the TXT content must be preceded with a backslash (
"This \"is\" valid"
For a literal backslash in the TXT record, escape it:
"This is also \\ valid"
Unicode characters can be added in two ways, either by adding the character itself
or the escaped variant to the content field. e.g.
"ç" is equal to
When a TXT record is longer than 255 characters/bytes (excluding possible enclosing quotes), PowerDNS will cut up the content into 255 character/byte chunks for transmission to the client.
The following, rarely used or obsolete record types, are also supported: