WinRM - the specified credentials were rejected by the server
<p>I am unable to get WinRM session in a python script.</p>

<h2>Environment</h2>

<pre><code>ad-dns.test.com    - Windows 2012 AD and DNS Server
box88.test.com     - CentOS 7.2 : Kerberos, Python (Not joined to domain)
box62.test.com     - Windows 2012 R2 Standard (Joined to domain)
box63.test.com     - Windows 10 (Joined to domain)
</code></pre>

<hr>

<h2>Configurations</h2>

<p>I have enabled WinRM on Windows 10 and 2012 server through <a href="https://github.com/ansible/ansible/blob/devel/examples/scripts/ConfigureRemotingForAnsible.ps1" rel="noreferrer">ConfigureRemotingForAnsible.ps1</a> PowerShell script. These are the WinRM configurations.</p>

<pre><code>PS C:\Windows\system32&gt; winrm get winrm/config
Config
    MaxEnvelopeSizekb = 500
    MaxTimeoutms = 60000
    MaxBatchItems = 32000
    MaxProviderRequests = 4294967295
    Client
        NetworkDelayms = 5000
        URLPrefix = wsman
        AllowUnencrypted = false
        Auth
            Basic = true
            Digest = true
            Kerberos = true
            Negotiate = true
            Certificate = true
            CredSSP = false
        DefaultPorts
            HTTP = 5985
            HTTPS = 5986
        TrustedHosts = *
    Service
        RootSDDL = O:NSG:BAD:P(A;;GA;;;BA)(A;;GR;;;IU)S:P(AU;FA;GA;;;WD)(AU;SA;GXGW;;;WD)
        MaxConcurrentOperations = 4294967295
        MaxConcurrentOperationsPerUser = 1500
        EnumerationTimeoutms = 240000
        MaxConnections = 300
        MaxPacketRetrievalTimeSeconds = 120
        AllowUnencrypted = false
        Auth
            Basic = true
            Kerberos = true
            Negotiate = true
            Certificate = false
            CredSSP = false
            CbtHardeningLevel = Relaxed
        DefaultPorts
            HTTP = 5985
            HTTPS = 5986
        IPv4Filter = *
        IPv6Filter = *
        EnableCompatibilityHttpListener = false
        EnableCompatibilityHttpsListener = false
        CertificateThumbprint
        AllowRemoteAccess = true
    Winrs
        AllowRemoteShellAccess = true
        IdleTimeout = 7200000
        MaxConcurrentUsers = 10
        MaxShellRunTime = 2147483647
        MaxProcessesPerShell = 25
        MaxMemoryPerShellMB = 1024
        MaxShellsPerUser = 30
PS C:\Windows\system32&gt; 
</code></pre>

<p>I have prepared CentOS box as below</p>

<pre><code># yum -y install python-pip python-devel krb5-devel krb5-libs krb5-workstation
# pip install --upgrade pip
# pip install  "pywinrm&gt;=0.1.1" kerberos pykerberos requests-kerberos isodate xmltodict

# cat /etc/krb5.conf
[libdefaults]
 default_realm = TEST.COM

[realms]
 TEST.COM = {
  kdc = ad-dns.test.com
  admin_server   = ad-dns.test.com
  kpasswd_server = ad-dns.test.com
  default_domain = test.com
 }

[domain_realm]
 .test.com = TEST.COM
 test.com = TEST.COM
#

# kinit vkumar@TEST.COM
Password for vkumar@TEST.COM:
# klist
Ticket cache: FILE:/tmp/krb5cc_0
Default principal: vkumar@TEST.COM

Valid starting       Expires              Service principal
2016-06-30T02:15:20  2016-06-30T12:15:20  krbtgt/TEST.COM@TEST.COM
    renew until 2016-07-01T02:15:16
#
</code></pre>

<h2>Problem</h2>

<p>Until now, everything appears smooth. The problem occurs when I try to use this kerberos ticket to authenticate the Windows servers using the below script.</p>

<pre><code>#!/usr/bin/env python

import winrm

s = winrm.Session('box63.test.com', auth=('vkumar@TEST.COM', 'IamUsingKerbTicket'), transport='kerberos')
r = s.run_cmd('ipconfig', ['/all'])
print r.status_code
print r.std_out
print r.std_err


# ./winrm_ipconfig.py
Traceback (most recent call last):
  File "./winrm_ipconfig.py", line 6, in &lt;module&gt;
    r = s.run_cmd('ipconfig', ['/all'])
  File "/usr/lib/python2.7/site-packages/winrm/__init__.py", line 37, in run_cmd
    shell_id = self.protocol.open_shell()
  File "/usr/lib/python2.7/site-packages/winrm/protocol.py", line 132, in open_shell
    res = self.send_message(xmltodict.unparse(req))
  File "/usr/lib/python2.7/site-packages/winrm/protocol.py", line 207, in send_message
    return self.transport.send_message(message)
  File "/usr/lib/python2.7/site-packages/winrm/transport.py", line 179, in send_message
    raise InvalidCredentialsError("the specified credentials were rejected by the server")
winrm.exceptions.InvalidCredentialsError: the specified credentials were rejected by the server
#
</code></pre>

<p>Not sure, why I see this error while <code>Event Logs</code> on Windows server show success. Apparently, I see three <code>Logon</code> and <code>Logoff</code> occurring at the same time. 
<a href="https://i.stack.imgur.com/C520p.png" rel="noreferrer"><img src="https://i.stack.imgur.com/C520p.png" alt="Windows_Event_Logs"></a></p>

<p>Not sure what I am missing here. Firewall is stopped/disabled on both CentOS &amp; Windows machines and times are also in sync.</p>