客户问题概括：
用户反馈在域中一台Win 2003 SP2 服务器使用 Powershell ，“enter-pssession” 链接到另外一台服务器无法工作，该服务器无其他问题.
报错内容:
WSManFault
Message = WinRM cannot process the request. The following error occured while using Negotiate authentication: An unknown security error occurred.
Possible causes are:
-The user name or password specified are invalid.
-Kerberos is used when no authentication method and no user name are specified.
-Kerberos accepts domain user names, but not local user names.
-The Service Principal Name (SPN) for the remote computer name and port does not exist.
-The client and remote computers are in different domains and there is no trust between the two domains.
After checking for the above issues, try the following:
-Check the Event Viewer for events related to authentication.
-Change the authentication method; add the destination computer to the WinRM TrustedHosts configuration setting or use
HTTPS transport.
Note that computers in the TrustedHosts list might not be authenticated.
-For more information about WinRM configuration, run the following command: winrm help config.
解决方法：
排查安全日志发现此服务器SPN注册有问题,重新注册spn后即可, 注册spn工具为setspn.exe
举例:
setspn -l HTTP/Servername 确认SPN
setspn -q HTTP/Servername.fqdn
发现重复SPN
setspn -x删除重复spn
原文地址：http://blog.51cto.com/13133729/2063421