Software Update: PowerDNS Recursor 4.7.0

PowerDNS is a dns server with a database as backend, which makes it easy to manage a large number of dns entries. The developers have previously decided to release the two parts that make up PowerDNS, a recursor and an authoritative name server, to allow faster and more targeted release of a new version, the developers said.

When you perform a dns lookup, a recursor initially starts asking the lookup query to a dns root server. This can then redirect to other servers, from where it can redirect to other servers and so on, until finally a server is reached that knows the answer or knows that the look-up is not possible. The latter can be the case if the name does not exist or the servers do not respond. The process of going through different authoritative servers is called recursion. The developers have released PowerDNS Recursor 4.7.0 with the following announcement:

PowerDNS Recursor 4.7.0 Released

We are proud to announce the release of PowerDNS Recursor 4.7.0. Compared to the previous major (4.6) release of PowerDNS Recursor, this release contains the following major changes:

• A configurable way of adding Additional records to answers sent to the client, so the client does not have to ask for these records.
• The step sizes for Query Minimization are now computed following to guidelines in RFC 9156.
• The Recursor now schedules tasks to resolve IPv6 addresses of name servers not learned by glue records. This has the consequence that, if applicable, name servers will be contacted over IPv6 more often.
• An experimental implementation of unilateral DoT probing. This allows the Recursor to learn if a an authoritative servers supports DoT.
• Recursor has gained a way to fall back to the parent NS set if contacting servers in the child NS set does not lead to an answer. This works around some broken authoritative servers configurations.
• ZONEMD validation of the zones retrieved by the Zone to Cache, providing integrity guarantees for the zone retrieved.
• The table recording round trip times of authoritative server IP addresses is now shared between threads to make it more effective and to reduce its memory footprint.
• A Lua FFI hook for post-resolve interception: postresolve_ffi, providing a very fast way to do post-resolve Lua scripting.

As always, there are also many smaller bug fixes and improvements, please refer to the changelog for additional details. When upgrading don’t forget to check the upgrade guide.

Please send us all feedback and issues you might have via the mailing list, or in case of a bug, via GitHub.

The tarball (signature) is available from our download server and packages for several distributions are available from our repository.

With this 4.7.0 release, the 4.4.x releases will be EOL and the 4.5.x and 4.6.x releases will go into critical fixes only mode. Consult the EOL policy for more details.

We would also like to mention that with the 4.5 release we stopped supporting systems using 32-bit time. This includes most 32-bit Linux platforms.

We also like to announce the upcoming removal of XPF support. If you are using this feature, plan switching to the proxy protocol.

We are grateful to the PowerDNS community for the reporting of bugs, issues, feature requests, and especially to the submitters of fixes and implementations of features.