diff --git a/pyipmi/errors.py b/pyipmi/errors.py
index 9d10cc1..2c1dbfe 100644
--- a/pyipmi/errors.py
+++ b/pyipmi/errors.py
@@ -99,3 +99,12 @@ def __init__(self, msg=None):
 
     def __str__(self):
         return "{}".format(self.msg)
+
+
+class AuthenticationError(Exception):
+    """Authentication error."""
+    def __init__(self, msg=None):
+        self.msg = msg
+
+    def __str__(self):
+        return "{}".format(self.msg)
diff --git a/pyipmi/interfaces/ipmitool.py b/pyipmi/interfaces/ipmitool.py
index d0adb2e..8b92146 100644
--- a/pyipmi/interfaces/ipmitool.py
+++ b/pyipmi/interfaces/ipmitool.py
@@ -21,7 +21,12 @@
 from array import array
 
 from ..session import Session
-from ..errors import IpmiTimeoutError, IpmiConnectionError, IpmiLongPasswordError
+from ..errors import (
+    IpmiTimeoutError,
+    IpmiConnectionError,
+    IpmiLongPasswordError,
+    AuthenticationError,
+)
 from ..logger import log
 from ..msgs import encode_message, decode_message, create_message
 from ..msgs.constants import CC_OK
@@ -64,6 +69,8 @@ def __init__(self, interface_type='lan', cipher=None):
                 r".*Could not open device.*")
         self.re_long_password = re.compile(
                 r".*password is longer than.*")
+        self.re_authentication_error = re.compile(
+                r".*RAKP [0-9]+ HMAC.*")
         self._session = None
 
     def open(self):
@@ -89,6 +96,7 @@ def rmcp_ping(self):
         cmd += (' -I %s' % self._interface_type)
         cmd += (' -H %s' % self._session.rmcp_host)
         cmd += (' -p %s' % self._session.rmcp_port)
+        cmd += (' -v')
         if self._session.auth_type == Session.AUTH_TYPE_NONE:
             cmd += (' -A NONE')
         elif self._session.auth_type == Session.AUTH_TYPE_PASSWORD:
@@ -142,13 +150,19 @@ def _parse_output(self, output):
             if self.re_long_password.match(line):
                 raise IpmiLongPasswordError(line)
 
+            if self.re_authentication_error.match(line):
+                raise AuthenticationError('Authentication error')
+
             hexstr += line.replace('\r', '').strip() + ' '
 
         hexstr = hexstr.strip()
         if len(hexstr):
-            rsp = array('B', [
-                int(value, 16) for value in hexstr.split(' ')
-            ])
+            try:
+                rsp = array('B', [
+                    int(value, 16) for value in hexstr.split(' ')
+                ])
+            except ValueError:
+                pass
 
         return cc, rsp
 
@@ -250,6 +264,7 @@ def _build_ipmitool_cmd(self, target, lun, netfn, raw_bytes):
         cmd += (' -I %s' % self._interface_type)
         cmd += (' -H %s' % self._session.rmcp_host)
         cmd += (' -p %s' % self._session.rmcp_port)
+        cmd += (' -v')
 
         cmd += self._build_ipmitool_priv_level(self._session.priv_level)
 
diff --git a/tests/interfaces/test_ipmitool.py b/tests/interfaces/test_ipmitool.py
index 4ae59bd..de8c0bf 100644
--- a/tests/interfaces/test_ipmitool.py
+++ b/tests/interfaces/test_ipmitool.py
@@ -5,7 +5,7 @@
 
 import pytest
 
-from pyipmi.errors import IpmiTimeoutError, IpmiConnectionError, IpmiLongPasswordError
+from pyipmi.errors import IpmiTimeoutError, IpmiConnectionError, IpmiLongPasswordError, AuthenticationError
 from pyipmi.interfaces import Ipmitool
 from pyipmi import Session, Target
 from pyipmi.utils import py3_array_tobytes
@@ -53,7 +53,7 @@ def test_rmcp_ping(self):
 
         self._interface.rmcp_ping()
         mock.assert_called_once_with('ipmitool -I lan -H 10.0.1.1 -p 623 '
-                                     '-U "admin" -P "secret" '
+                                     '-v -U "admin" -P "secret" '
                                      'session info all')
 
     def test_send_and_receive_raw_valid(self):
@@ -65,7 +65,7 @@ def test_send_and_receive_raw_valid(self):
         self._interface.send_and_receive_raw(target, 0, 0x6, b'\x01')
 
         mock.assert_called_once_with('ipmitool -I lan -H 10.0.1.1 -p 623 '
-                                     '-L ADMINISTRATOR -U "admin" -P "secret" '
+                                     '-v -L ADMINISTRATOR -U "admin" -P "secret" '
                                      '-t 0x20 -l 0 raw 0x06 0x01 2>&1')
 
     def test_send_and_receive_raw_lanplus(self):
@@ -80,7 +80,7 @@ def test_send_and_receive_raw_lanplus(self):
         interface.send_and_receive_raw(target, 0, 0x6, b'\x01')
 
         mock.assert_called_once_with('ipmitool -I lanplus -H 10.0.1.1 -p 623 '
-                                     '-L ADMINISTRATOR -U "admin" -P "secret" '
+                                     '-v -L ADMINISTRATOR -U "admin" -P "secret" '
                                      '-t 0x20 -l 0 raw 0x06 0x01 2>&1')
 
     def test_send_and_receive_raw_cipher(self):
@@ -95,7 +95,7 @@ def test_send_and_receive_raw_cipher(self):
         interface.send_and_receive_raw(target, 0, 0x6, b'\x01')
 
         mock.assert_called_once_with('ipmitool -I lan -H 10.0.1.1 -p 623 '
-                                     '-L ADMINISTRATOR -C 7 '
+                                     '-v -L ADMINISTRATOR -C 7 '
                                      '-U "admin" -P "secret" '
                                      '-t 0x20 -l 0 raw 0x06 0x01 2>&1')
 
@@ -110,7 +110,7 @@ def test_send_and_receive_raw_no_auth(self):
         self._interface.send_and_receive_raw(target, 0, 0x6, b'\x01')
 
         mock.assert_called_once_with('ipmitool -I lan -H 10.0.1.1 -p 623 '
-                                     '-L ADMINISTRATOR -P "" '
+                                     '-v -L ADMINISTRATOR -P "" '
                                      '-t 0x20 -l 0 raw 0x06 0x01 2>&1')
 
     def test_send_and_receive_raw_return_value(self):
@@ -236,3 +236,9 @@ def test_parse_long_password_error(self):
         with pytest.raises(IpmiLongPasswordError):
             cc, rsp = self._interface._parse_output(test_str)
             assert rsp is None
+
+    def test_parse_output_authentication_error(self):
+        test_str = b'Loading ...\nUsing ...\n> RAKP 2 HMAC is invalid\nError:'
+        with pytest.raises(AuthenticationError):
+            cc, rsp = self._interface._parse_output(test_str)
+            assert rsp is None