Technical stuff that might be useful

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  • Windows update CAB file build up

    We’ve had a spate of PCs filling up their disks recently, and it seems to stem from a bug in Windows update.

    The issue occurs because an accumulated update log file grows, and generates a series of CAB files “cab_xxx_x” in the temp folder (normally c:\windows\temp).

    The issue isn’t new, I found references to it dating back to 2012. It seems to be a bug with Windows Update on Windows 7 and Windows Server 2008 R2.

    If you just delete the CAB files they will come back. The solution seems to be to do the run the following commands:

    net stop wuauserv 
    net stop trustedinstaller

    rmdir /s c:\windows\softwaredistribution
    del c:\windows\temp\*.* /s /f /q

    net start wuauserv
    net start trustedinstaller

    If you don’t stop the services first you may not be able to delete the files.

    Next step is to run Windows update. Windows 7 and 2008 R2 have a huge number of updates to do from a fresh install, which is why this log file builds up. Deleting the files resets the log, but if there are still too many to do the issue may come back.

    I set up a monitor on SolarWinds N-Central to check all our clients temp folder sizes and to run the above as a script if it was over 15GB. That should prevent any space issues on-going.

    Alternatively just upgrade to Windows 10 and Server 2016 – they don’t have this problem.

  • Using Office 365 as your SMTP server on a 3CX PBX

    If you want to use Office 365 as your SMTP email server for a 3CX PBX you are best setting up a Connector on the Exchange Online account. I am assuming that your PBX is on the end of a static IP address.

    First configure your 3CX server. Under Email and settings set the mail server to match your MX record. This usual follows the format domain.mail.protection.outlook.com where domain is your email domain with hyphens instead of dots.

    Set a reply to address on the same domain. I always use pbx @ sfax.co.uk, it doesn’t go anywhere, I don’t expect anyone to reply to it.

    You don’t need a username or password or to enable SSL/TLS as we will set up a connector to receive the email.

    Next log on to your Office 365 portal as an administrator, and open your Exchange Admin Center. From there pick connectors under mail flow.

    Create a new Connector.

    Pick from: Your organization’s email server

    To: Office 365

    Give it an appropriate name:

    Next select By Verifying that the IP address of the sending server matches one of these addresses that belong to your organization

    Click the plus to add an IP address and enter your PBX’s internet IP address

    Save the connector and you are good to go.

    http://3cx.co.uk

    http://portal.office.com

  • Manually syncing Azure AD

    When Azure Connect is setup the quickest way to fire off a manual sync is through powershell.

    For a full sync (new accounts etc):

    import-module adsync
    Start-ADSyncSyncCycle -PolicyType Initial

    For a incremental sync (faster but not as thorough):

    import-module adsync
    Start-ADSyncSyncCycle -PolicyType delta

    I normally save these as .ps1 files on the desktop of the server to I can quickly run them.

    [3cx-clicktotalk id=”89″ title=”Live Chat & Talk item 1″]

  • Moving FSMO Roles with Powershell

    Another article about a command that I can never remember the syntax when I need it.

    The information here is from: https://social.technet.microsoft.com/wiki/contents/articles/6736.move-transfering-or-seizing-fsmo-roles-with-ad-powershell-command-to-another-domain-controller.aspx

    To transfer all roles use:

    Move-ADDirectoryServerOperationMasterRole -Identity “Target-DC” -OperationMasterRole SchemaMaster,RIDMaster,InfrastructureMaster,DomainNamingMaster,PDCEmulator

    To seize the roles append -Force.

    You can also substitute the role names with numbers, making a more manageable:

    Move-ADDirectoryServerOperationMasterRole -Identity “Target-DC” -OperationMasterRole 0,1,2,3,4 -Force

    Much easier to remember than trying to remember which bit of the gui does which role.

    Older servers use ntdsutil.exe:

    https://support.microsoft.com/en-gb/help/255504/using-ntdsutil.exe-to-transfer-or-seize-fsmo-roles-to-a-domain-controller

  • Using subst to map a drive to help restore from a volume shadow copy

    I needed to copy only missing files from a volume shadow copy back to a clients share after clearing out crypto malware encrypted files, and I found a new favourite command:
    subst drive1: drive2:path
    Substitutes a path for a drive letter, for example:
    subst x: c:\users\adam\desktop

    maps x: to my desktop in my profile.

    Where this came in particular handy for me we using robocopy to restore files an folders out of a volume shadow copy (previous version).

    I wanted to run robocopy a: b: /xc /xn /xo /s which only copies missing files, and does not copy existing files – regardless of age or difference, to extract missing files from the shadow copy.

    So first I found the path to the file by right clicking on a file in the shadow copy and copying the location then running subst:

    subst x: "\\localhost\C$\@GMT-2016.10.24-14.01.30\Server Shares\Company"

    I could then run my robocopy from the x: drive.

    Finished off with subst x: /d to remove the drive mapping.

    Useful write up here:

    https://chaoliu12.wordpress.com/2013/02/11/restore-files-from-shadow-copy/

    And subst technet article here:

    https://technet.microsoft.com/en-gb/library/bb491006.aspx

  • User Shell Folders location in the registry

    I’m always having to look this up, for some reason the registry location just doesn’t stick in my head.

    User Shell Folders (i.e. My Documents, Desktop, Favorites):

    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders

    Useful if you want to know if Folder Redirection is working.

  • Extracting useful user information from Exchange 2010 with Powershell

    Finishing a migration to Office 365 and want to send the client a list of remaining user mailboxes that need moving (or deleting!).

    get-mailbox and get-mailboxstatistics both have their uses, but I really needed to use something that combined them both.

    I found the solution at https://www.experts-exchange.com/questions/28399371/Combining-Get-Mail-Get-Mailboxstatistics-To-Pull-UsageLocation-LastLogonTime.html

    And adapted it to my own means:

    Get-Mailbox -ResultSize Unlimited | sort-object | Select-Object Name, primarysmtpaddress, @{n="Mailbox Size";e = {$MBXstat = Get-MailboxStatistics $_.name; $MBXstat.TotalItemSize}}, @{n="LastLogonTime";e = {$MBXstat = Get-MailboxStatistics $_.name; $MBXstat.LastLogonTime}} | Export-Csv C:\temp\LastLogonTime.csv

    This outputs the User name, Primary SMTP Address from get-mailbox and Mailbox size (formatted to MB) and last logon time from get-mailboxstatistics.

  • Reconnecting an Office 365 mailbox with an on-premise user

    Hybrid Office 365 setup. User account is created on-premise, AD is synced, and then the user is licenced as an Office 365 user. Exchange won’t create the Remote User forwarder, so the user will only receive email from Office 365 (and external if the MX record has been switched to Office 365).

    You can join the account up with the command:

    Enable-RemoteMailbox Username -RemoteRoutingAddress “username@tennent.mail.onmicrosoft.com”

    That will create the Remote Mailbox on Exchange with the forwarder email address.