Get-Mailbox -ResultSize:Unlimited | ForEach {Get-ActiveSyncDeviceStatistics -Mailbox:$_.Identity}

Get-Mailbox | Get-MailboxStatistics | sort-object TotalItemSize -desc |ft DisplayName, @{expression={$_.TotalItemSize.value.toMB()};label=”TotalItemSize(MB)”},ItemCount –auto

Launch the Exchange Management Console
Expand the Organization Configuration folder
Click on Hub Transport
Select Remote Domains (Key point)
Right-click Default (Tab)
Click on the Message Format (Tab)
To turn off NDR, remove the tick on Allow non-delivery reports.

Download

Import-ExchangeCertificate -Path C:\your_domain_name.cer | Enable-ExchangeCertificate -Services “SMTP, IMAP, POP, IIS”

Get-ExchangeCertificate

Enable-ExchangeCertificate -ThumbPrint [paste] -Services “SMTP, IMAP, POP, IIS

New-ExchangeCertificate -GenerateRequest -Path c:\Common Name.csr -KeySize 2048 -SubjectName “c=DK, s=State, l=City, o=Organization, ou=Department, cn=Common Name” -DomainName Subject, Alternative, Names -PrivateKeyExportable $True

For some reason when you use the Public Folders tool in Exchange 2007 SP1 you can’t change the client permissions for the public folders.  So to do so, follow the below steps:

1) Logon to your ‘Exchange 2007′ server.

2) Open the ‘Exchange Management Shell’.

3) Type the below, replaceing ‘public folder name’ with your public folder name/path and you must keep the \ at the front of it and also replace ‘username’ with the username:

Add-PublicFolderClientPermission -Identity “\public folder name” -AccessRights Owner -User username

That’s it, just repeat for any other public folders that you wish to change the permissions on.

The above example is to assign Owner permissions to the user, but you can replace Owner with the below:

• None
• Owner
• PublishingEditor
• Editor
• PublishingAuthor
• Author
• Non-EditingAuthor
• Reviewer
• Contributor

Basically what you should do is to enable the Recipient Filtering functionality to block emails addressed to invalid recipients.
 
In this manner emails will be rejected immediately without generating an NDR.
 
You can only do this if Exchange is receiving internet email directly.
 
If you have the Ex2007 Edge Transport go to:
Microsoft Exchange | Edge Transport | Anti-Spam
 
Otherwise for Ex2007 Hub Transport install the anti-spam agents:
http://support.microsoft.com/kb/555924

Next go to:
Microsoft Exchange | Organization Configuration | Hub Transport | Anti-Spam
 
Open the properties for  Recipient Filtering and tick the checkbox:
‘Block messages sent to recipients not listed in the Global Address List’

Exchange 2007 has a built in anti-spam filtering module that just needs to be enabled.

Here are some simple instructions to get going with it. Once you’ve enabled this feature, you should see an anti-spam tab in the Exchange management console under Organization configuration > Hub Transport > Anti-Spam.

To enable anti-spam functionality on a Hub Transport server

1. Open the Exchange Management Shell

2. cd to the scripts folder in the Exchange install directory.
%system drive%/Program Files\Microsoft\Exchange Server\Scripts folder.

3. Run the following command:

./install-AntispamAgents.ps1

4. After the script has run, restart the Microsoft Exchange Transport service by running the following command:

Restart-Service MSExchangeTransport

5. Enable automatic anti-spam updates.