--- a/src/imap/ngx_imap_handler.c
+++ b/src/imap/ngx_imap_handler.c
@@ -7,17 +7,21 @@
 
 
 static void ngx_imap_init_session(ngx_event_t *rev);
+static void ngx_pop3_auth_state(ngx_event_t *rev);
+static ngx_int_t ngx_pop3_read_command(ngx_imap_session_t *s);
 
 
-static char pop3_greeting[] = "+OK " NGINX_VER " ready" CRLF;
-static char imap_greeting[] = "* OK " NGINX_VER " ready" CRLF;
+static u_char pop3_greeting[] = "+OK " NGINX_VER " ready" CRLF;
+static u_char imap_greeting[] = "* OK " NGINX_VER " ready" CRLF;
+
+static u_char pop3_ok[] = "+OK" CRLF;
+static u_char pop3_invalid_command[] = "-ERR invalid command" CRLF;
 
 
 void ngx_imap_init_connection(ngx_connection_t *c)
 {
-    char       *greeting;
-    ssize_t     size;
-    ngx_int_t   n;
+    u_char   *greeting;
+    ssize_t   size;
 
     ngx_log_debug0(NGX_LOG_DEBUG_IMAP, c->log, 0,
                    "imap init connection");
@@ -27,9 +31,7 @@ void ngx_imap_init_connection(ngx_connec
     greeting = pop3_greeting;
     size = sizeof(pop3_greeting) - 1;
 
-    n = ngx_send(c, greeting, size);
-
-    if (n < size) {
+    if (ngx_send(c, greeting, size) < size) {
         /*
          * we treat the incomplete sending as NGX_ERROR
          * because it is very strange here
@@ -50,11 +52,14 @@ void ngx_imap_init_connection(ngx_connec
 
 static void ngx_imap_init_session(ngx_event_t *rev)
 {
+    size_t               size;
     ngx_connection_t    *c;
     ngx_imap_session_t  *s;
 
     c = rev->data;
 
+    /* TODO: timeout */
+
     if (!(s = ngx_pcalloc(c->pool, sizeof(ngx_imap_session_t)))) {
         ngx_imap_close_connection(c);
         return;
@@ -68,16 +73,113 @@ static void ngx_imap_init_session(ngx_ev
         return;
     }
 
-    s->buffer = ngx_create_temp_buf(s->connection->pool, /* STUB */ 4096);
+    size = /* STUB: pop3: 128, imap: configurable 4K default */ 128;
+
+    s->buffer = ngx_create_temp_buf(s->connection->pool, size);
     if (s->buffer == NULL) {
         ngx_imap_close_connection(s->connection);
         return;
     }
 
-    ngx_imap_proxy_init(s);
+    ngx_pop3_auth_state(rev);
+}
+
+
+static void ngx_pop3_auth_state(ngx_event_t *rev)
+{
+    u_char              *text;
+    ssize_t              size;
+    ngx_int_t            rc;
+    ngx_connection_t    *c;
+    ngx_imap_session_t  *s;
+
+    c = rev->data;
+    s = c->data;
+
+    /* TODO: timeout */
+
+    rc = ngx_pop3_read_command(s);
+
+    if (rc == NGX_AGAIN || rc == NGX_ERROR) {
+        return;
+    }
+
+    s->state = 0;
+
+    if (rc == NGX_IMAP_PARSE_INVALID_COMMAND) {
+        text = pop3_invalid_command;
+        size = sizeof(pop3_invalid_command) - 1;
+
+    } else {
+        text = pop3_ok;
+        size = sizeof(pop3_ok) - 1;
+    }
+
+    if (ngx_send(c, text, size) < size) {
+        /*
+         * we treat the incomplete sending as NGX_ERROR
+         * because it is very strange here
+         */
+        ngx_imap_close_connection(c);
+        return;
+    }
 }
 
 
+static ngx_int_t ngx_pop3_read_command(ngx_imap_session_t *s)
+{
+    ssize_t    n;
+    ngx_int_t  rc;
+
+    n = ngx_recv(s->connection, s->buffer->last,
+                 s->buffer->end - s->buffer->last);
+
+    if (n == NGX_ERROR || n == 0) {
+        ngx_imap_close_connection(s->connection);
+        return NGX_ERROR;
+    }
+
+    if (n > 0) {
+        s->buffer->last += n;
+    }
+
+    if (n == NGX_AGAIN) {
+        if (ngx_handle_read_event(s->connection->read, 0) == NGX_ERROR) {
+            ngx_imap_close_connection(s->connection);
+            return NGX_ERROR;
+        }
+
+        return NGX_AGAIN;
+    }
+
+    rc = ngx_pop3_parse_command(s);
+
+    if (rc == NGX_AGAIN || rc == NGX_IMAP_PARSE_INVALID_COMMAND) {
+        return rc;
+    }
+
+    if (rc == NGX_ERROR) {
+        ngx_imap_close_connection(s->connection);
+        return NGX_ERROR;
+    }
+
+    return NGX_OK;
+}
+
+
+#if 0
+
+void ngx_imap_close_session(ngx_imap_session_t *s)
+{
+    ngx_log_debug0(NGX_LOG_DEBUG_IMAP, s->connection->log, 0,
+                   "close imap session");
+
+    ngx_imap_close_connection(s->connection);
+}
+
+#endif
+
+
 void ngx_imap_close_connection(ngx_connection_t *c)
 {
     ngx_log_debug1(NGX_LOG_DEBUG_IMAP, c->log, 0,