diff --git a/build-constraints.yaml b/build-constraints.yaml
index d7cb23bb..55ed1cb4 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -1416,6 +1416,9 @@ expected-test-failures:
     # https://github.com/ekmett/semigroupoids/issues/34
     - semigroupoids
 
+    # https://github.com/kazu-yamamoto/dns/issues/29
+    - dns
+
 # Haddocks which are expected to fail. Same concept as expected test failures.
 expected-haddock-failures:
     # https://github.com/acw/bytestring-progress/issues/4