bits from the release team

curl dns 2026, part III, async

In part I and part II I talked about the changes to DNS resolution in curl and why we do them. In this post I cover the difference and changes in synchronous vs asynchronous resolution. Which matter for Happy Eyeballs v3 (HEv3) and Encrypted Client Hellos (ECH). Sync/Async, Old and New Out of all the DNS options I described in part II, the most compatible and most deployed one is getaddrinfo(). Sync, no threads or c-ares

curl dns 2026, part II, options

In part I I talked about the changes to DNS resolution in curl and why we do them. In order to see where they apply and if/under which conditions you benefit, we need to shine some light on what “DNS resolution” in curl is. Options As you probably know, curl and libcurl is available on many platforms with capabilities that vary greatly. This also applies to DNS resolution. One configures at build time what mechanism to use. That might require additional libraries like c-ares. Not enough flexibility? You can also at runtime tell curl to use DNS-over-HTTPS (DoH).