Normally, with an Office 365 mailbox, you can only send mails with the primary email address. Sending from aliases was not allowed. Microsoft recently rolled out this feature which can be enabled through Exchange Online PowerShell:
If you are having performance issues with your brand new File Server running on Windows Server 2019, particularly when working with small files over a network share, these PowerShell commands might save hours of troubleshooting.
Alternatively, you can add the DWORD ZeroConfigExchangeOnce 1 key to automate the creation of the first profile. Successful profiles have to be created manually.
If you have an AD synced distribution group and want to only allow senders from your organization, the msExchRequireAuthToSendTo attribute must be set to TRUE in the Attribute Editor. If you try changing that in the Exchange Online console, an error will appear.
When syncing local AD users to Azure AD, you can configure Seamless Sign-On to automatically login to Microsoft 365 Apps like Sharepoint Online, OneDrive, or Exchange Online. This is very easy to do and will make logins for users less painful.
When the pre-checks is complete, hit configure and exit.
A Computer Account named AZUREADSSOACC will be created in Active Directory which allows the authentication validation between Azure AD and local Active Directory. The Kerberos decryption key is saved in the cloud and should be changed regularly. You can see that on the Computer account, service principal names are configured
Lastly, you can roll out the feature with Group Policy. The URL https://autologon.microsoftazuread-sso.com must be added to the intranet zone list, which allows the browser to send Kerberos tickets to that site.
The GPO can be found under User Configuration > Policies > Administrative Templates > Windows Components > Internet Explorer > Internet Control Panel > Security Page > Site to Zone Assignment List.
Status bar updates via script must be also enabled. This GPO is located under User Configuration > Policies > Administrative Templates > Windows Components > Internet Explorer > Internet Control Panel > Security Page > Intranet Zone > Allow updates to status bar via script.
You can test the feature by opening portal.office.com. After entering the username, login should be done automatically without needing to insert a password.
