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Fedora will attempt to use DNS over TLS (DoT) if supported by configured DNS servers.


Current status

  • Targeted release: Fedora 34
  • Last updated: 2020-09-28
  • FESCo issue: <will be assigned by the Wrangler>
  • Tracker bug: <will be assigned by the Wrangler>
  • Release notes tracker: <will be assigned by the Wrangler>

Detailed Description

We will build systemd with -Ddefault-dns-over-tls=opportunistic to protect DNS queries against passive. An active network attacker can trivially subvert this b

Note that DoT is different from DNS over HTTPS (DoH). In particular, DoT is not an anti-censorship tool. It does not look like regular HTTPS traffic, and can be blocked by network administrators if desired.


Benefit to Fedora

DNS queries are encrypted and private by default, if the user's ISP supports DNS over TLS. Most probably don't, but users who manually configure a custom DNS server (e.g. Cloudflare or Google) will automatically benefit from DNS over TLS.


  • Proposal owners: change meson flags in systemd.spec
  • Other developers: N/A (nothing should be required)
  • Release engineering: #9772 (a check of an impact with Release Engineering is needed)
  • Policies and guidelines: N/A (nothing should be required)
  • Trademark approval: N/A (not needed for this Change)
  • Alignment with Objectives: Nope

Upgrade/compatibility impact

DoT will be enabled automatically on upgrade to F34. If DoT is unsupported, systemd-resolved will fall back to unencrypted DNS, so there should be no compatibility impact.

How To Test


User Experience

Users should not notice any difference in behavior, unless checking how DNS is sent in Wireshark.


No dependencies.

Contingency Plan

  • Contingency mechanism: revert the change
  • Contingency deadline: F34 beta freeze
  • Blocks release? No
  • Blocks product? No


See the section DNSOverTLS= in the manpage resolved.conf(5)

Release Notes