diff --git a/tests-extra/tools/dnstest/server.py b/tests-extra/tools/dnstest/server.py
index 87d1d3b37b851ffe7827e359faea681b1bd819d5..c1254f53d6c7ec96d4403c43ccb8cb72931c7311 100644
--- a/tests-extra/tools/dnstest/server.py
+++ b/tests-extra/tools/dnstest/server.py
@@ -878,6 +878,7 @@ class Knot(Server):
         s.item("zonefile-sync", "0")
         s.item("notify-timeout", "5")
         s.item("notify-retries", "5")
+        s.item("semantic-checks", "on")
         if self.disable_any:
             s.item("disable-any", "on")
         if self.dnssec_enable: