--- a/src/mail/ngx_mail_smtp_handler.c
+++ b/src/mail/ngx_mail_smtp_handler.c
@@ -467,6 +467,10 @@ ngx_mail_smtp_auth_state(ngx_event_t *re
         }
     }
 
+    if (s->buffer->pos < s->buffer->last) {
+        s->blocked = 1;
+    }
+
     switch (rc) {
 
     case NGX_DONE:
@@ -488,11 +492,14 @@ ngx_mail_smtp_auth_state(ngx_event_t *re
 
     case NGX_OK:
         s->args.nelts = 0;
-        s->buffer->pos = s->buffer->start;
-        s->buffer->last = s->buffer->start;
+
+        if (s->buffer->pos == s->buffer->last) {
+            s->buffer->pos = s->buffer->start;
+            s->buffer->last = s->buffer->start;
+        }
 
         if (s->state) {
-            s->arg_start = s->buffer->start;
+            s->arg_start = s->buffer->pos;
         }
 
         ngx_mail_send(c->write);
@@ -506,7 +513,7 @@ ngx_mail_smtp_helo(ngx_mail_session_t *s
     ngx_str_t                 *arg;
     ngx_mail_smtp_srv_conf_t  *sscf;
 
-    if (s->args.nelts != 1) {
+    if (s->args.nelts != 2) {
         s->out.len = sizeof(smtp_invalid_argument) - 1;
         s->out.data = smtp_invalid_argument;
         s->state = 0;
@@ -515,14 +522,14 @@ ngx_mail_smtp_helo(ngx_mail_session_t *s
 
     arg = s->args.elts;
 
-    s->smtp_helo.len = arg[0].len;
+    s->smtp_helo.len = arg[1].len;
 
-    s->smtp_helo.data = ngx_pnalloc(c->pool, arg[0].len);
+    s->smtp_helo.data = ngx_pnalloc(c->pool, arg[1].len);
     if (s->smtp_helo.data == NULL) {
         return NGX_ERROR;
     }
 
-    ngx_memcpy(s->smtp_helo.data, arg[0].data, arg[0].len);
+    ngx_memcpy(s->smtp_helo.data, arg[1].data, arg[1].len);
 
     s->smtp_from.len = 0;
     s->smtp_from.data = NULL;
@@ -576,7 +583,7 @@ ngx_mail_smtp_auth(ngx_mail_session_t *s
     }
 #endif
 
-    if (s->args.nelts == 0) {
+    if (s->args.nelts < 2) {
         s->out.len = sizeof(smtp_invalid_argument) - 1;
         s->out.data = smtp_invalid_argument;
         s->state = 0;
@@ -634,9 +641,7 @@ ngx_mail_smtp_auth(ngx_mail_session_t *s
 static ngx_int_t
 ngx_mail_smtp_mail(ngx_mail_session_t *s, ngx_connection_t *c)
 {
-    u_char                     ch;
-    ngx_str_t                  l;
-    ngx_uint_t                 i;
+    ngx_str_t                 *arg, *end, cmd;
     ngx_mail_smtp_srv_conf_t  *sscf;
 
     sscf = ngx_mail_get_module_srv_conf(s, ngx_mail_smtp_module);
@@ -659,37 +664,20 @@ ngx_mail_smtp_mail(ngx_mail_session_t *s
         return NGX_OK;
     }
 
-    l.len = s->buffer->last - s->buffer->start;
-    l.data = s->buffer->start;
-
-    for (i = 0; i < l.len; i++) {
-        ch = l.data[i];
-
-        if (ch != CR && ch != LF) {
-            continue;
-        }
-
-        l.data[i] = ' ';
-    }
+    arg = s->args.elts;
+    end = arg + s->args.nelts - 1;
 
-    while (i) {
-        if (l.data[i - 1] != ' ') {
-            break;
-        }
+    cmd.len = end->data + end->len - arg->data;
+    cmd.data = arg->data;
 
-        i--;
-    }
+    s->smtp_from.len = cmd.len;
 
-    l.len = i;
-
-    s->smtp_from.len = l.len;
-
-    s->smtp_from.data = ngx_palloc(c->pool, l.len);
+    s->smtp_from.data = ngx_palloc(c->pool, cmd.len);
     if (s->smtp_from.data == NULL) {
         return NGX_ERROR;
     }
 
-    ngx_memcpy(s->smtp_from.data, l.data, l.len);
+    ngx_memcpy(s->smtp_from.data, cmd.data, cmd.len);
 
     s->out.len = sizeof(smtp_ok) - 1;
     s->out.data = smtp_ok;
@@ -701,9 +689,7 @@ ngx_mail_smtp_mail(ngx_mail_session_t *s
 static ngx_int_t
 ngx_mail_smtp_rcpt(ngx_mail_session_t *s, ngx_connection_t *c)
 {
-    u_char      ch;
-    ngx_str_t   l;
-    ngx_uint_t  i;
+    ngx_str_t  *arg, *end, cmd;
 
     if (s->smtp_from.len == 0) {
         s->out.len = sizeof(smtp_bad_sequence) - 1;
@@ -711,37 +697,20 @@ ngx_mail_smtp_rcpt(ngx_mail_session_t *s
         return NGX_OK;
     }
 
-    l.len = s->buffer->last - s->buffer->start;
-    l.data = s->buffer->start;
-
-    for (i = 0; i < l.len; i++) {
-        ch = l.data[i];
-
-        if (ch != CR && ch != LF) {
-            continue;
-        }
-
-        l.data[i] = ' ';
-    }
+    arg = s->args.elts;
+    end = arg + s->args.nelts - 1;
 
-    while (i) {
-        if (l.data[i - 1] != ' ') {
-            break;
-        }
+    cmd.len = end->data + end->len - arg->data;
+    cmd.data = arg->data;
 
-        i--;
-    }
+    s->smtp_to.len = cmd.len;
 
-    l.len = i;
-
-    s->smtp_to.len = l.len;
-
-    s->smtp_to.data = ngx_palloc(c->pool, l.len);
+    s->smtp_to.data = ngx_palloc(c->pool, cmd.len);
     if (s->smtp_to.data == NULL) {
         return NGX_ERROR;
     }
 
-    ngx_memcpy(s->smtp_to.data, l.data, l.len);
+    ngx_memcpy(s->smtp_to.data, cmd.data, cmd.len);
 
     s->auth_method = NGX_MAIL_AUTH_NONE;