macOS 26 breaks custom DNS settings including .internal
A critical bug in macOS 26 has broken the long-standing /etc/resolver/ mechanism for custom TLDs, causing local development environments and private networks to fail as mDNSResponder incorrectly intercepts unicast DNS queries.
The latest macOS 26 update has introduced a critical bug that breaks the long-standing /etc/resolver/ mechanism for custom Top-Level Domains (TLDs). This feature, documented in man 5 resolver, allows developers to route specific domain queries (like *.test or *.internal) to local DNS servers such as dnsmasq. In macOS 26, mDNSResponder incorrectly intercepts these queries as multicast DNS (mDNS) instead of consulting the specified unicast nameservers. This silent failure affects a wide range of professional workflows, including local web development, Docker container resolution, and Kubernetes tools. Currently, the only workaround is manually editing the /etc/hosts file, which is impractical for dynamic environments. Developers are calling for an urgent fix from Apple to restore this essential networking functionality.
Source: Hacker News
