How to alter the Kerberos time synchronization tolerance

Kerberos is a time sensitive authentication system. This is good. The time tolerance helps to prevent a replay attack. You can make this tolerance more or less stricter then the default of 5 minutes. Network packets for Kerberos authentication that have a time stamp within the tolerance value, as compared to the domain controllers clock, is considered valid.

For a local computer, you would open the local security policy.

For a domain joined computer, open a GPO that applies to the client.

For a Domain Controller, open the Default Domain Policy GPO.

Expand: Computer Configuration / Policies / Windows Settings / Security Settings / Account Policies

Open Maximum tolerance for computer clock synchronization

Check Define this policy setting.

Enter in the number of minutes you will allow clocks to be out of sync and click OK

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How to list all the AD LDS instances on a server

AD LDS allows you to provide directory services to applications that are free of the confines of Active Directory. To list all the AD LDS instances on a server, follow this procedure: Log into the server in question Open a command prompt. Type dsdbutil and press Enter Type List Instances and press Enter . You will receive a list of the instance name, both the LDAP and SSL port numbers, the location of the database, and its status.

How to run GPResult on a remote client with PowerShell

In the past, to run the GPResult command, you would need to either physically visit this client, have the user do it, or use and RDP connection. In all cases, this will disrupt the user. First, you need PowerShell remoting enabled on the target machine. You can do this via Group Policy . Open PowerShell and type this command. Invoke-Command –ScriptBlock {GPResult /r} –ComputerName <ComputerName> Replace <ComputerName> with the name of the target. Remember, the target needs to be online and accessible to you.

Where did a User’s Account Get Locked Out?

Updated: May 15, 2015 When this article was originally published, two extra carriage returns were add causing the code to malfunction. The code below is correct. My client for this week’s PowerShell class had a really interesting question. They needed to know where an account is being locked out at. OK, interesting. Apparently users hop around clients and forget to log off, leading to eventual lock out of their accounts. The accounts can be unlocked, but are then relocked after Active Directory replication. This problem is solved in two parts. The first one is to modify the event auditing on the network. The second part is resolved with PowerShell. The first part involves creating a group policy that will encompass your Domain Controllers. In this GPO, make these changes. Expand Computer Configuration \ Policies \ Windows Settings \ Security Settings \ Advanced Audit Policy Configuration \ Audit Policies \ Account Management Double click User Account Management C...

Jason Yoder, MCT

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