diff --git a/src/core/ngx_resolver.c b/src/core/ngx_resolver.c
index 02c484d..ecf97d7 100644
--- a/src/core/ngx_resolver.c
+++ b/src/core/ngx_resolver.c
@@ -1834,6 +1834,10 @@
     p--;
     *p-- = '\0';
 
+    if (ctx->name.len == 0)  {
+        return NGX_DECLINED;
+    }
+
     for (s = ctx->name.data + ctx->name.len - 1; s >= ctx->name.data; s--) {
         if (*s != '.') {
             *p = *s;