Enable Or Disable External Mail

Enable or disable external parties to send emails to a Microsoft 365 group

Description

This runbook configures whether external senders are allowed to email a Microsoft 365 group. It uses Exchange Online to enable or disable the RequireSenderAuthenticationEnabled setting. You can also query the current state without making changes.

Location

Group → Mail → Enable Or Disable External Mail

Full Runbook name

rjgit-group_mail_enable-or-disable-external-mail

Details

Property	Value
Version	1.0.1
Required modules	ExchangeOnlineManagement (>= 3.9.2) RealmJoin.RunbookHelper (>= 0.8.9)
Schedulable	no

Notes

Setting this via Microsoft Graph is broken as of 2021-06-28. Attribute: allowExternalSenders. See https://docs.microsoft.com/en-us/graph/known-issues#setting-the-allowexternalsenders-property.

Permissions

Application permissions

• Type: Office 365 Exchange Online

  • Exchange.ManageAsApp

    • Runs Get-/Set-UnifiedGroup to toggle RequireSenderAuthenticationEnabled in the app-only session

RBAC roles

• Exchange Administrator

  • Required for the app-only Exchange Online session changing the external mail setting

Parameters

GroupId

Object ID of the Microsoft 365 group.

Property	Value
Required	true
Default Value
Type	String
Hidden in portal	yes (preset via runbook customization)

Action

"Enable External Mail" (final value: 0), "Disable External Mail" (final value: 1) or "Query current state only" (final value: 2) can be selected as action to perform. If set to 0, the runbook will allow external senders to email the group. If set to 1, it will block external senders from emailing the group. If set to 2, it will return whether external mailing is currently enabled or disabled for the group without making any changes.

Property	Value
Required	false
Default Value	0
Type	Int32
Portal display name	Choose action

Portal options

Portal option	Value
Enable External Mail	0
Disable External Mail	1
Query current state only	2

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