diff --git a/dns/resolver.go b/dns/resolver.go
index 96da175..fa20764 100644
--- a/dns/resolver.go
+++ b/dns/resolver.go
@@ -162,7 +162,7 @@ func (r *Resolver) exchangeWithoutCache(ctx context.Context, m *D.Msg) (msg *D.M
 
 			msg := result.(*D.Msg)
 
-			putMsgToCache(r.lruCache, q.String(), msg)
+			putMsgToCache(r.lruCache, q.String(), q, msg)
 		}()
 
 		isIPReq := isIPRequest(q)
diff --git a/dns/util.go b/dns/util.go
index 05c734e..90d2ff9 100644
--- a/dns/util.go
+++ b/dns/util.go
@@ -16,9 +16,9 @@ import (
 	D "github.com/miekg/dns"
 )
 
-func putMsgToCache(c *cache.LruCache, key string, msg *D.Msg) {
+func putMsgToCache(c *cache.LruCache, key string, q D.Question, msg *D.Msg) {
 	// skip dns cache for acme challenge
-	if q := msg.Question[0]; q.Qtype == D.TypeTXT && strings.HasPrefix(q.Name, "_acme-challenge") {
+	if q.Qtype == D.TypeTXT && strings.HasPrefix(q.Name, "_acme-challenge.") {
 		log.Debugln("[DNS] dns cache ignored because of acme challenge for: %s", q.Name)
 		return
 	}