diff --git a/src/shared/dns-domain.c b/src/shared/dns-domain.c
index 7a2c5d60f4..60560654bd 100644
--- a/src/shared/dns-domain.c
+++ b/src/shared/dns-domain.c
@@ -1413,5 +1413,9 @@ bool dns_name_dont_resolve(const char *name) {
         if (dns_name_endswith(name, "invalid") > 0)
                 return true;
 
+        /* Never respond to some of the domains listed in RFC9476 */
+        if (dns_name_endswith(name, "alt") > 0)
+                return true;
+
         return false;
 }
diff --git a/test/units/testsuite-75.sh b/test/units/testsuite-75.sh
index dbcb53d72b..e039e4ebc2 100755
--- a/test/units/testsuite-75.sh
+++ b/test/units/testsuite-75.sh
@@ -317,6 +317,7 @@ FILTERED_NAMES=(
     "255.255.255.255.in-addr.arpa"
     "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa"
     "hello.invalid"
+    "hello.alt"
 )
 
 for name in "${FILTERED_NAMES[@]}"; do