Warn before sending emails to external domains in Outlook

Thanks ojhhawkins for the code above - really useful. I've done a simple iteration to include a list of the external email addresses in the MsgBox text.

Word of caution - I've noticed that the warning doesn't appear when you use the Send As Email Attachment in other programmes, eg Excel, Adobe Reader etc. As niton pointed out:

Re:Send As Email Attachment in other programmes. Described in notes here outlookcode.com/d/code/setsavefolder.htm "... does not work on messages created with File | Send commands in Office programs or similar commands in Windows Explorer or other programs. Those commands invoke Simple MAPI, which bypasses Outlook functionality."

Private Sub Application_ItemSend(ByVal Item As Object, Cancel As Boolean)    Dim recips As Outlook.Recipients    Dim recip As Outlook.Recipient    Dim pa As Outlook.PropertyAccessor    Dim prompt As String    Dim strMsg As String    Const PR_SMTP_ADDRESS As String = "http://schemas.microsoft.com/mapi/proptag/0x39FE001E"    Set recips = Item.Recipients    For Each recip In recips        Set pa = recip.PropertyAccessor        If InStr(LCase(pa.GetProperty(PR_SMTP_ADDRESS)), "@example.com") = 0 Then            strMsg = strMsg & "   " & pa.GetProperty(PR_SMTP_ADDRESS) & vbNewLine        End If    Next    If strMsg <> "" Then        prompt = "This email will be sent outside of example.com to:" & vbNewLine & strMsg & "Do you want to proceed?"        If MsgBox(prompt, vbYesNo + vbExclamation + vbMsgBoxSetForeground, "Check Address") = vbNo Then            Cancel = True        End If    End IfEnd Sub

To actually add this code to your Outlook application:

• If you can't see the Developer tab in the ribbon bar, go to File/Options, choose Customise Ribbon on the left, and tick Developer on the right.
• From the Developer tab choose Visual Basic.
• Expand Project1, Microsoft Outlook Objects, and double-click ThisOutlookSession (top left).
• Paste the code above into the module.
• Replace the "example.com" in the copied code to your domain.
• Close the VBA editor and save changes to the module.
• On the Developer tab click Macro Security, and change the level to Notifications for all macros or lower.
• Restart Outlook. (The code above will not initialise otherwise.)

1. Add the below code to the Application_ItemSend event in Outlook & change the domain to your own

2. Change the Macro Security to either (Notifcations for all macros or Enable all macros)

This will provide you with a warning before sending if 1 or more of your TO,CC or BCC address is not in your domain (eg below @mycompany.com.au)

Private Sub Application_ItemSend(ByVal Item As Object, Cancel As Boolean)    Dim recips As Outlook.Recipients    Dim recip As Outlook.Recipient    Dim pa As Outlook.PropertyAccessor    Const PR_SMTP_ADDRESS As String = "http://schemas.microsoft.com/mapi/proptag/0x39FE001E"    Set recips = Item.Recipients    For Each recip In recips        Set pa = recip.PropertyAccessor        If InStr(LCase(pa.GetProperty(PR_SMTP_ADDRESS)), "@mycompany.com.au") = 0 Then            If MsgBox("Send mail to external domain?", vbYesNo + vbQuestion + vbMsgBoxSetForeground, "Check Address") = vbNo Then                Cancel = True                Exit Sub            Else                Exit Sub            End If        End If    NextEnd Sub

I found two add-ins for Outlook that does the same if you don't want to use VBA,

• www.safesendsoftware.com and
• www.sperrysoftware.com.