commit - 521607802a026aae130395eb147b81d480b94e34
commit + 20fd186cb05aed778db0ee7d84c3e413e3ad68fe
blob - 015729f39f39fb70f98b95524ea9c361113fabc9
blob + dd7b5f2f459e6e76827e5b097efb0938d67b0156
--- dns.go
+++ dns.go
@@ -161,6 +161,8 @@ func exchange(msg dnsmessage.Message, conn net.Conn) (
 	}
 	if rmsg.Header.ID != msg.Header.ID {
 		return rmsg, errMismatchedID
+	} else if rmsg.Questions[0] != msg.Questions[0] {
+		return rmsg, fmt.Errorf("mismatched response to question")
 	}
 	return rmsg, nil
 }