What’s New in dnspython


This release has no new features, but fixes the following issues:

  • dns.zone.from_text failed if relativize was False and an origin was specified in the parameters.

  • A number of types permitted an empty “rest of the rdata”.

  • L32, L64, LP, and NID were missing from dns/rdtypes/ANY/__init__.py

  • The type definition for dns.resolver.resolve_address() was incorrect.

  • dns/win32util.py erroneously had the executable bit set.

  • The type definition for a number of asynchronous query routines was missing the default of None for the backend parameter.

  • dns/tsigkeyring.py didn’t import dns.tsig.

  • A number of rdata types that have a “rest of the line” behavior for the last field of the rdata erroneously permitted an empty string.

  • Timeout intervals are no longer reported with absurd precision in exception text.


  • SVCB and HTTPS records have been updated to track the evolving draft standard.

  • The ZONEMD type has been added.

  • The resolver now returns a LifetimeTimeout exception which includes an error trace like the NoNameservers exception. This class is a subclass of dns.exception.Timeout for backwards compatibility.

  • DNS-over-HTTPS will try to use HTTP/2 if the httpx and h2 packages are installed.

  • DNS-over-HTTPS is now supported for asynchronous queries and resolutions.

  • dns.zonefile.read_rrsets() has been added, which allows rrsets in zonefile format, or a restrition of it, to be read. This function is useful for applications that want to read DNS data in text format, but do not want to use a Zone.

  • On Windows systems, if the WMI module is available, the resolver will retrieve the nameserver from WMI instead of trying to figure it out by reading the registry. This may lead to more accurate results in some cases.

  • The CERT rdatatype now supports certificate types IPKIX, ISPKI, IPGP, ACPKIX, and IACPKIX.

  • The CDS rdatatype now allows digest type 0.

  • Dnspython zones now enforces that a node is either a CNAME node or an “other data” node. A CNAME node contains only CNAME, RRSIG(CNAME), NSEC, RRSIG(NSEC), NSEC3, or RRSIG(NSEC3) rdatasets. An “other data” node contains any rdataset other than a CNAME or RRSIG(CNAME) rdataset. The enforcement is “last update wins”. For example, if you have a node which contains a CNAME rdataset, and then add an MX rdataset to it, then the CNAME rdataset will be deleted. Likewise if you have a node containing an MX rdataset and add a CNAME rdataset, the MX rdataset will be deleted.

  • Extended DNS Errors, as specified in RFC 8914, are now supported.

See the 2.2 project on github or the git change log for more details.


  • End-of-line comments are now associated with rdata when read from text. For backwards compatibility with prior versions of dnspython, they are only emitted in to_text() when requested.

  • Synchronous I/O is a bit more efficient, as we now try the I/O and only use poll() or select() if the I/O would block.

  • The resolver cache classes now offer basic hit and miss statistics, and the LRUCache can also provide hits for every cache key.

  • The resolver has a canonical_name() method.

  • There is now a registration mechanism for EDNS option types.

  • The default EDNS payload size has changed from 1280 to 1232.

  • The SVCB, HTTPS, and SMIMEA RR types are now supported.

  • TSIG has been enhanced with TKEY and GSS-TSIG support. Thanks to Nick Hall for writing this.

  • Zones now can be updated via transactions.

  • A new zone subclass, dns.versioned.Zone is available which has a thread-safe transaction implementation and support for keeping many versions of a zone.

  • The zone file reading code has been adapted to use transactions, and is now a public API.

  • Inbound zone transfer support has been rewritten and is available as dns.query.inbound_xfr() and dns.asyncquery.inbound_xfr(). It uses the transaction mechanism, and fully supports IXFR and AXFR.


  • Python 3.6 or newer is required.

  • The license is now the ISC license.

  • Rdata is now immutable. Use dns.rdata.Rdata.replace() to make a new Rdata based on an existing one.

  • dns.resolver.resolve() has been added, allowing control of whether search lists are used. dns.resolver.query() is retained for backwards compatibility, but deprecated. The default for search list behavior can be set at in the resolver object with the use_search_by_default parameter. The default is False.

  • DNS-over-TLS is supported with dns.query.tls().

  • DNS-over-HTTPS is supported with dns.query.https(), and the resolver will use DNS-over-HTTPS for a nameserver which is an HTTPS URL.

  • Basic query and resolver support for the Trio, Curio, and asyncio asynchronous I/O libraries has been added in dns.asyncquery and dns.asyncresolver. This API should be viewed as experimental as asynchronous I/O support in dnspython is still evolving.

  • TSIG now defaults to using SHA-256.

  • Basic type info has been added to some functions. Future releases will have comprehensive type info.

  • from_text() functions now have a relativize_to parameter.

  • python-cryptography is now used for DNSSEC.

  • Ed25519 and Ed448 signatures are now supported.

  • A helper for NSEC3 generating hashes has been added.

  • SHA384 DS records are supported.

  • Rdatasets and RRsets are much faster.

  • dns.resolver.resolve_address() has been added, allowing easy address-to-name lookups.

  • dns.reversename functions now allow an alternate origin to be specified.

  • The repr form of Rdatasets and RRsets now includes the rdata.

  • A number of standard resolv.conf options are now parsed.

  • The nameserver and port used to get a response are now part of the resolver’s Answer object.

  • The NINFO record is supported.

  • The dns.hash module has been removed; just use Python’s native hashlib module.

  • Rounding is done in the standard python 3 fashion; dnspython 1.x rounded in the python 2 style on both python 2 and 3.

  • The resolver will now do negative caching if a cache has been configured.

  • TSIG and OPT now have rdata types.

  • The class for query messages is now QueryMessage. Class Message is now a base class, and is also used for messages for which we don’t have a better class. Update messages are now class UpdateMessage, though class Update is retained for compatibility.

  • Support for Windows 95, 98, and ME has been removed.