DHCP migration between different server languages

Sometime happen (hopefully) that you have to dismiss old and not supported Operating System (aka Windows 2003) and during the process you need to move the DHCP server.

If both server have the same language, you will not face any problem but, if source and target server are in different languages (sometime, for no good reasons, IT technicians install the OS in their own language instead of English), the import process will fail to match the correspondent DHCP class.

The error raise is: Error while importing class “Default BOOTP Class”. This class conflicts with the existing class “Default BOOTP Class”.

Here the manual workaround to solve this.

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Exchange Server Object ID Error

I had an error with Exchange Control Panel and Windows 2016 Domain Controller: The access control entry defines the ObjectType ‘9b026da6-0d3c-465c-8bee-5199d7165cba’ that can’t be resolved.

Exchange Error

The error will be raised as you open the ECP and view the Mailbox Delegation tab of any user account. Moreover this error doesn’t appear if you have an hybrid deployment with Office 365. Read More

CredSSP: RDP problem when not all the systems are update

In April 2018 Microsoft released an update to address a specific CVE that involve Credential Security Support Provider protocol (CredSSP): CVE-2018-0886 

This update was released for all the supported Windows Operating Systems. Even though I recommend to keep your server up to date, most of the customers don’t have automatic procedure to update the systems on regular basis (SCCM could be the right answer).

Here is where problems start.


An update client with 2018-05 Update try to connect to a servers without the May update or vice versa a client without the update try to connect to a server with the May update installed.

In both situation the same error pop up:

An authentication error has occurred. The function requested is not supported. Remote computer: <computer name or IP>. This could be due to CredSSP encryption oracle remediation. For more information, see https://go.microsoft.com/fwlink/?linkid=866660.

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Troubleshooting Office 365

I would to share some advance Office 365 troubleshooting techniques I used to investigate problems with sign-in, activation, authentication, installation and update.

Troubleshooting Authentication/Sign-in/Activation Errors

To investigate about random user problem, usually sign-in prompt, you should enable Office 365 logging and compare a “working attempt” vs a “non working attempt” to compare the results.

Launch cmd as administrator and run the following command:

reg add HKCU\SOFTWARE\Microsoft\Office\15.0\Common\Debug /v TCOTrace /t REG_DWORD /d 1 /f

Once the error occurs collect the following logs:

Collect logs from %temp%
<appname>.exe.log (where <appname> is the name of the application used for the Sign-In attempt, for example, Excel.exe.log or Winword.exe.log)

Remove the regkey added. To do this, launch cmd as administrator and run the following command:

reg delete HKCU\SOFTWARE\Microsoft\Office\15.0\Common\Debug /v TCOTrace /f

Note: if you are, as in my case, in a RDS environment, you should create a GPO to deploy/remove this registry key and cooperate with the users to collect logs when error popup

Enable O365 Logs GPO Read More

Guest Access in SMB2 disabled on 1709 version of Windows 10 and Windows Server 2016

When you try to access to a consumer or old NAS with your brand new Windows 10 Fall Creators Update you will face a network access error.
Due to security issue in SMB protocol, the new Windows 10 and Windows Server 2016 release 1709 start with some SMB feature disabled by default:

  • SMBv1 not installed (enable it with Enable-WindowsOptionalFeature -Online -FeatureName SMB1Protocol)
  • SMBv2 Guest Access disabled

As Microsoft state:
In Windows 10 Fall Creators Update and Windows Server version 1709, the SMB2 client no longer allows the following actions:

  • Guest account access to a remote server
  • Fallback to the Guest account after invalid credentials are provided

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Windows 10 Fall Creators Update

Windows 10 Fall Creators Update was released and I want to point at some enterprise features we could rely on (most of them are in Client Hyper-V feature).
Please refer to Windows 10 Blog to read about all the new features added with this release.

Ransomware protections.

Microsoft are introducing Windows Defender Exploit Guard that helps protect files from unauthorized changes by nefarious applications and your applications from unknown exploits. Additionally, Windows Defender Antivirus now has specific safeguards in place, along with default enhanced coverage that is delivered instantly via the cloud protection service. These and other security technologies protect against persistent ransomware campaigns like Cerber, Locky, and Spora, as well as global outbreaks like WannaCry, and Petya. Read More

Outlook mobile end of support for iOS 9

Outlook for iOS
Apple iOS 11

Due to the rapid changes of mobile device OS and Office 365 specifications, Microsoft release a communication to inform us to update your Apple devices to a new iOS version to have a better Outlook for iOS compatibility:

With the release of iOS 11, we want to remind you that Outlook for iOS is supported only in the last two releases of iOS. This means new app updates to Outlook will now only be supported on devices with iOS 10 or iOS 11.
How does this affect me?
You are receiving this message because our reporting indicates one or more users in your organization are using Outlook for iOS on iOS 9.

Devices with iOS 9 are no longer be supported. While older versions of Outlook will still work on devices running iOS 9, these devices will not get new app updates after build 2.48. Users can expect a degraded experience of the Outlook for iOS app over time, if they do not stay up-to-date.
What do I need to do to prepare for this change?
We encourage you to stay up-to-date to maintain the best Office 365 experience.

Rif.: https://products.office.com/en-us/office-system-requirements#Mobile-devices-section

Certification Authority Enhanced RPC security

Certification Authority 2012/2012R2 and XP clients

Some Customers still have Windows XP though it is in End of Support since 8 April 2014. I found one of this *#$%§ clients where I have an 802.1x implementation with an Enterprise Certification Authority with Windows Server 2012 R2.

Why I detailed my configuration? Because Windows 2012 and newer raised RPC security settings even on PKI CA and this cause failing certificate requests on Windows XP/Windows Server 2003.
When trying to issue certificate on Windows XP I got the error “The certificate request failed. The permissions on this certification authority do not allow the current user to enroll for certificates. ”

At first glance it has to be Permissions issue but when I verify them on CA and on the template level they are ok. If we go to the “Failed Request” container on CA we cannot see any request which has been denied by the CA. This is because the request is never delivered to the server.

So how to let Windows XP enroll certificates from Windows 2012/2012R2 Certification Authority?

  1. Upgrade Windows clients to higher OS as XP is not supported anymore
  2. Disable Enhanced RPC security for certificate requests

In my case, the first option wasn’t viable.

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AD FS & Office 365 Multi Domain Federation

Often happen that a customer has more then one email domain in his On-Premises infrastructure. This should be considered when you plan to deploy AD FS Services to enable Single Sign-On with Office 365.
With the newest version of Azure AD Connect, steps to federate On Premises AD DS with Azure AD is fully automated though it assumes that the domain specified during the wizard steps is the only one domain you want to federate (If you need an overview of Azure AD Connect step-by-step configuration, please refer to Microsoft Docs here).

This will cause disruption of users login to Office 365 apps. To solve this situation you need to change the federation mode configured by the wizard manually using Powershell and set it to a Multi Domain federation. Read More