FOSDEM 2025, the Free and Open Source Software Developers’ European Meeting, took place on February 1st and 2nd, 2025, at the Université Libre de Bruxelles (ULB) in Brussels. As one of the largest non-commercial events for open-source software developers, FOSDEM once again brought together thousands of participants from around the world to exchange ideas and collaborate on projects. Although the event took place a few weeks ago and we’ve been quite busy since, we still wanted to take a moment to share a recap and our key takeaways.
Beyond the many talks and discussions with fellow open-source enthusiasts, the highlight for our PowerDNS engineers was, of course, the DNS Devroom. We were honored to co-organize this track and were thrilled with the diverse lineup of speakers and topics. If you missed any of the sessions, you can catch up by following the recordings linked below.
The day kicked off with Valentin Gosu and his talk, “getaddrinfo sucks, everything else is much worse.” He explored the challenges of working with the getaddrinfo API in Firefox and shared insights into alternative APIs that help improve DNS resolution. When a last-minute speaker cancellation occurred, PowerDNS engineer Otto Moerbeek and longtime community contributor Kevin P. Fleming stepped in to fill the gap. Their session, “Catalog Zones in the PowerDNS Recursor,” explained how forward definitions in PowerDNS Recursor must stay in sync with an authoritative server’s configuration. Traditionally, this required manual updates or custom scripts, but with catalog zones, the process can now be fully automated, ensuring all forwards remain perfectly aligned.
Farzaneh Badiei also stepped in on short notice with her talk, “Is Big DNS Taking Over?”. She raised concerns about the decreasing number of trusted public DNS resolvers and how their usage has declined significantly in many regions over the past years. Next, Alexander Bokovoy shared insights from FreeIPA and Samba teams in his talk, “DNS for enterprise domains: FreeIPA and Samba AD experience.” He discussed the DNS requirements of enterprise environments and how these projects address them.
In his session, “NetBox DNS - Single source of truth for DNS,” Peter Eckel introduced a small NetBox plugin designed to simplify DNS management. Initially built for a specific customer, the tool eventually evolved into a moderately complex yet powerful DNS management solution. Alexey Milovidov took the stage with his talk, “rDNS Map In Your Hands,” sharing unusual and amusing insights from the process of creating an rDNS map, taking the opportunity to also promote Clickhouse as a data store. Mark Overmeer’s session, “Prove website, domain, and network ownership,” focused on various methods for establishing proof of website ownership. He also raised important questions about how domain and network (IP-range) ownership can be expressed in DNS.
At PowerDNS, we were particularly excited for Fastly’s Kevin P. Fleming other talk, “Modern zone replication using LMDB and Lightning Stream.” As a follow-up to his FOSDEM 2023 presentation, “Hosting your own DNS for ‘fun’ and zero profit,” Kevin shared his latest experiences using Lightning Stream for zone replication between PowerDNS Authoritative Servers. Spoiler alert: Kevin had a fantastic experience! He highlighted Lightning Stream’s low resource consumption, its ability to support ephemeral server deployments, and the lack of complexity when managing database systems. We got some great questions about how such a deployment would differ from traditional ones based on AXFR or database replication.
We ended with two talks about optimizing software. Ondřej Surý discussed in “how to make BIND 9 fast(er)” how BIND 9 is being modernized to tackle challenges such as better scalability, lower memory usage, and an improved architecture that leverages modern CPUs. Closing out the day, PowerDNS colleagues Rémi Gacogne and Peter van Dijk presented “Honey, I shrunk DNSdist.” They shared how PowerDNS adapted DNSdist — our DNS proxy with support for DoT, DoH, DoH/3, and DoQ — to bring encryption to embedded devices running OpenWrt. They also discussed the challenges of reducing DNSdist’s footprint while maintaining end-to-end encrypted DNS services for home users.
A huge thank you to all the speakers, organizers, and attendees who made the DNS Devroom at FOSDEM 2025 such a success! We gained many valuable insights and are already looking forward to another great edition in 2026.
If you have any questions about the DNS Devroom, the presentations, or anything PowerDNS-related, feel free to reach out!
