--- a/src/core/ngx_resolver.c
+++ b/src/core/ngx_resolver.c
@@ -578,6 +578,7 @@ failed:
 ngx_int_t
 ngx_resolve_addr(ngx_resolver_ctx_t *ctx)
 {
+    u_char               *name;
     ngx_resolver_t       *r;
     ngx_resolver_node_t  *rn;
 
@@ -601,19 +602,21 @@ ngx_resolve_addr(ngx_resolver_ctx_t *ctx
 
             ngx_queue_insert_head(&r->addr_expire_queue, &rn->queue);
 
-            ctx->name.len = rn->nlen;
-            ctx->name.data = ngx_resolver_dup(r, rn->name, rn->nlen);
-            if (ctx->name.data == NULL) {
+            name = ngx_resolver_dup(r, rn->name, rn->nlen);
+            if (name == NULL) {
                 goto failed;
             }
 
+            ctx->name.len = rn->nlen;
+            ctx->name.data = name;
+
             /* unlock addr mutex */
 
             ctx->state = NGX_OK;
 
             ctx->handler(ctx);
 
-            ngx_resolver_free(r, ctx->name.data);
+            ngx_resolver_free(r, name);
 
             return NGX_OK;
         }
@@ -623,7 +626,9 @@ ngx_resolve_addr(ngx_resolver_ctx_t *ctx
             ctx->next = rn->waiting;
             rn->waiting = ctx;
 
-            return NGX_AGAIN;
+            /* unlock addr mutex */
+
+            return NGX_OK;
         }
 
         ngx_queue_remove(&rn->queue);
@@ -1306,7 +1311,7 @@ ngx_resolver_process_a(ngx_resolver_t *r
              ctx->handler(ctx);
         }
 
-        if (naddrs) {
+        if (naddrs > 1) {
             ngx_resolver_free(r, addrs);
         }
 
@@ -1483,20 +1488,23 @@ ngx_resolver_process_ptr(ngx_resolver_t 
         goto short_response;
     }
 
-    len -= 2;
-
     if (ngx_resolver_copy(r, &name, buf, &buf[i], &buf[n]) != NGX_OK) {
         return;
     }
 
     ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver an:%V", &name);
 
-    if (len != (size_t) rn->nlen || ngx_strncmp(name.data, rn->name, len) != 0)
+    if (name.len != (size_t) rn->nlen
+        || ngx_strncmp(name.data, rn->name, name.len) != 0)
     {
-        ngx_resolver_free(r, rn->name);
+        if (rn->nlen) {
+            ngx_resolver_free(r, rn->name);
+        }
+
+        rn->nlen = (u_short) name.len;
         rn->name = name.data;
 
-        name.data = ngx_resolver_dup(r, rn->name, len);
+        name.data = ngx_resolver_dup(r, rn->name, name.len);
         if (name.data == NULL) {
             goto failed;
         }

--- a/src/mail/ngx_mail_smtp_handler.c
+++ b/src/mail/ngx_mail_smtp_handler.c
@@ -12,6 +12,7 @@
 
 
 static void ngx_mail_smtp_resolve_addr_handler(ngx_resolver_ctx_t *ctx);
+static void ngx_mail_smtp_resolve_name(ngx_event_t *rev);
 static void ngx_mail_smtp_resolve_name_handler(ngx_resolver_ctx_t *ctx);
 static void ngx_mail_smtp_greeting(ngx_mail_session_t *s, ngx_connection_t *c);
 static void ngx_mail_smtp_invalid_pipelining(ngx_event_t *rev);
@@ -88,9 +89,8 @@ ngx_mail_smtp_init_session(ngx_mail_sess
 static void
 ngx_mail_smtp_resolve_addr_handler(ngx_resolver_ctx_t *ctx)
 {
-    ngx_connection_t          *c;
-    ngx_mail_session_t        *s;
-    ngx_mail_core_srv_conf_t  *cscf;
+    ngx_connection_t    *c;
+    ngx_mail_session_t  *s;
 
     s = ctx->data;
     c = s->connection;
@@ -131,6 +131,23 @@ ngx_mail_smtp_resolve_addr_handler(ngx_r
     ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0,
                    "address resolved: %V", &s->host);
 
+    c->read->handler = ngx_mail_smtp_resolve_name;
+
+    ngx_post_event(c->read, &ngx_posted_events);
+}
+
+
+static void
+ngx_mail_smtp_resolve_name(ngx_event_t *rev)
+{
+    ngx_connection_t          *c;
+    ngx_mail_session_t        *s;
+    ngx_resolver_ctx_t        *ctx;
+    ngx_mail_core_srv_conf_t  *cscf;
+
+    c = rev->data;
+    s = c->data;
+
     cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module);
 
     ctx = ngx_resolve_start(cscf->resolver, NULL);