Anonymous Emails Between On-Premises and Exchange Online

Posted on 1 CommentPosted in Authentication, EOP, exchange, exchange online, Exchange Online Protection, Exchange Server, hybrid, smtp, spam

When you set up Exchange Hybrid, it should configure your Exchange organizations (both on-premises and cloud) to support the fact that an email from a person in one of the organizations should appear as internal to a recipient in the other organization. In Outlook that means you will see “Display Name” at the top of the message and not “Display Name” <email address>. An email from the internet is rightly treated as anonymous and so should appear as “Display Name” <email address> but when it comes from your on-premises environment or your cloud tenant it should be authenticated.

In the email headers you should see a header called AuthAs that reads internal. The SCL (Spam Confidence Level) should always be –1 and you should not have a header called X-CrossPremisesHeadersFilteredBySendConnector visible on internal emails.

Your hybrid setup can be incorrectly configured and cause this, and depending upon what Exchange Server version you are running and when you last ran the hybrid wizard you can end up with different results.

Lets take a quick view to some of the settings you should see:

  1. Exchange Server 2010 (with or without Edge Server 2010)
    1. Hybrid wizard will use Remote Domains to control internal vs external and authentication state. You should have a Remote Domain for tenant.mail.onmicrosoft.com that shows TNEFEnabled, TrustedMailOutboundEnabled, TargetDeliverDomain, and IsInternal all set to True on-premises
    2. TrustedMailnboundEnabled attribute is set to True on Get-RemoteDomain domain.com in the cloud
    3. The AllowedOOFType, which controls Out Of Office is set to InternalLegacy
  2. Exchange Server 2013 and later
    1. Your “Outbound to Office 365” send connector on-premises should have CloudServicesMailEnabled set to True
    2. The Remote Domains matter for Out of Office and moderated emails/voting buttons, but not for authentication as mentioned in #1 above
    3. The Inbound Connector for “Inbound from GUID” should have CloudServicesMailEnabled set to True
  3. Exchange Server 2010 with Exchange Server 2013 or later Edge (no 2013 on-premises, only Edge)
    1. The setting CloudServicesMailEnabled needs to be True, but 2010 does not support this setting, so you need to edit the directory using ADSIEdit and change the msExchSmtpSendFlags on the send connector from 64 to 131136. All this does is tell the 2013 or later Edge to enable CloudServicesMailEnabled
    2. See https://support.microsoft.com/en-us/help/3212872/email-sent-from-an-on-premises-exchange-2013-edge-transport-server-to for the steps to do this
  4. As #3 but with 2010 and 2013 on-premises – run the cmdlets and hybrid wizard from the 2013 server and not connected to the 2010 server!

Outlook Authentication Broken–Username and Password Missing

Posted on Leave a commentPosted in Authentication, windows 10, windows 7

I came across an issue recently where the Outlook security dialog box popup was broken. Rather than looking as below, the username and password fields where missing:

windows_security.jpg

The dialog box appeared as:

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Notice that the username and password fields are missing! Also missing, and the key to this issue, is the picture is missing too. This is usually an empty box, but for some companies they use Group Policy to push out a different graphic.

That image is a bitmap stored in “C:\ProgramData\Microsoft\User Account Pictures”.

At a client of mine, the marketing department had requested the company logo replace the user picture and provided at 1MB file for this purpose. The file was deployed to all machines and overwrote the user.bmp by way of GPO preferences. Resizing user.bmp to under 48K in “C:\ProgramData\Microsoft\User Account Pictures\” on a single machine resolved the issue for users on that computer. We then changed the source of the image to under 48K centrally to fix all users.

Note that this was Windows 7 – different file sizes and dimensions exist for different versions of Windows. For example a user.bmp file on Windows 10 can be 448×448 and the default is just under 600KB. So again, the 1MB file mentioned above might also break Windows 10, but to fix the issue on that OS I probably dont need to reduce the file size so small.

Azure AD SSO and Disabled Computer Accounts

Posted on 5 CommentsPosted in Authentication, Azure Active Directory, Azure AD, Office, Office 365, SSO

When you set up Azure AD SSO, the Azure AD Connect application creates a computer account called AZUREADSSOACC. Do not disable this account, or SSO stops working.

I’ve had a few clients in the past week disable this when generally disabling all the computer accounts that have not logged in for X days.

Therefore if you have Azure AD SSO enabled, I suggest updating your documentation on disabling computer accounts – ‘cause not all computer accounts actually login as computers (I’m thinking Cluster services here as well) and consider actually whether or not disabling accounts for computers that are not logging in any more is necessary.

Then also take the AZUREADSSOACC account and set a description on it saying do not disable!

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