diff --git a/vtysh/vtysh_user.c b/vtysh/vtysh_user.c
new file mode 100644
index 0000000..b84da2e
--- /dev/null
+++ b/vtysh/vtysh_user.c
@@ -0,0 +1,191 @@
+/* User authentication for vtysh.
+ * Copyright (C) 2000 Kunihiro Ishiguro
+ *
+ * This file is part of GNU Zebra.
+ *
+ * GNU Zebra is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * GNU Zebra is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Zebra; see the file COPYING.  If not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.  
+ */
+
+#include <zebra.h>
+
+#include <pwd.h>
+
+#ifdef USE_PAM
+#include <security/pam_appl.h>
+#include <security/pam_misc.h>
+#endif /* USE_PAM */
+
+#include "memory.h"
+#include "linklist.h"
+#include "command.h"
+
+#ifdef USE_PAM
+static struct pam_conv conv = 
+{
+  misc_conv,
+  NULL
+};
+
+int
+vtysh_pam (char *user)
+{
+  int ret;
+  pam_handle_t *pamh = NULL;
+
+  /* Start PAM. */
+  ret = pam_start("zebra", user, &conv, &pamh);
+  /* printf ("ret %d\n", ret); */
+
+  /* Is user really user? */
+  if (ret == PAM_SUCCESS)
+    ret = pam_authenticate (pamh, 0);
+  /* printf ("ret %d\n", ret); */
+  
+#if 0
+  /* Permitted access? */
+  if (ret == PAM_SUCCESS)
+    ret = pam_acct_mgmt (pamh, 0);
+  printf ("ret %d\n", ret);
+
+  if (ret == PAM_AUTHINFO_UNAVAIL)
+    ret = PAM_SUCCESS;
+#endif /* 0 */
+  
+  /* This is where we have been authorized or not. */
+#ifdef DEBUG
+  if (ret == PAM_SUCCESS)
+    printf("Authenticated\n");
+  else
+    printf("Not Authenticated\n");
+#endif /* DEBUG */
+
+  /* close Linux-PAM */
+  if (pam_end (pamh, ret) != PAM_SUCCESS) 
+    {
+      pamh = NULL;
+      fprintf(stderr, "vtysh_pam: failed to release authenticator\n");
+      exit(1);
+    }
+
+  return ret == PAM_SUCCESS ? 0 : 1;
+}
+#endif /* USE_PAM */
+
+struct user
+{
+  char *name;
+  u_char nopassword;
+};
+
+struct list *userlist;
+
+struct user *
+user_new ()
+{
+  struct user *user;
+  user = XMALLOC (0, sizeof (struct user));
+  memset (user, 0, sizeof (struct user));
+  return user;
+}
+
+void
+user_free (struct user *user)
+{
+  XFREE (0, user);
+}
+
+struct user *
+user_lookup (char *name)
+{
+  struct listnode *nn;
+  struct user *user;
+
+  LIST_LOOP (userlist, user, nn)
+    {
+      if (strcmp (user->name, name) == 0)
+	return user;
+    }
+  return NULL;
+}
+
+void
+user_config_write ()
+{
+  struct listnode *nn;
+  struct user *user;
+
+  LIST_LOOP (userlist, user, nn)
+    {
+      if (user->nopassword)
+	printf (" username %s nopassword\n", user->name);
+    }
+}
+
+struct user *
+user_get (char *name)
+{
+  struct user *user;
+  user = user_lookup (name);
+  if (user)
+    return user;
+
+  user = user_new ();
+  user->name = strdup (name);
+  listnode_add (userlist, user);
+
+  return user;
+}
+
+DEFUN (username_nopassword,
+       username_nopassword_cmd,
+       "username WORD nopassword",
+       "\n"
+       "\n"
+       "\n")
+{
+  struct user *user;
+  user = user_get (argv[0]);
+  user->nopassword = 1;
+  return CMD_SUCCESS;
+}
+
+int
+vtysh_auth ()
+{
+  struct user *user;
+  struct passwd *passwd;
+
+  passwd = getpwuid (geteuid ());
+
+  user = user_lookup (passwd->pw_name);
+  if (user && user->nopassword)
+    /* Pass through */;
+  else
+    {
+#ifdef USE_PAM
+      if (vtysh_pam (passwd->pw_name))
+	exit (0);
+#endif /* USE_PAM */
+    }
+  return 0;
+}
+
+void
+vtysh_user_init ()
+{
+  userlist = list_new ();
+  install_element (CONFIG_NODE, &username_nopassword_cmd);
+}