> For the complete documentation index, see [llms.txt](https://docs.realmjoin.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.realmjoin.com/automation/runbooks/runbook-references/group/mail/enable-or-disable-external-mail.md).

# Enable Or Disable External Mail

Allow or block external senders for this Microsoft 365 group

### Description

Controls whether people outside the organization can send email to this Microsoft 365 group. The current setting can also be shown without changing it.

### Implementation notes

The setting is changed through Exchange Online (`RequireSenderAuthenticationEnabled`), not through Microsoft Graph. Writing the corresponding `allowExternalSenders` property of the group via Microsoft Graph is a documented known issue (as of 2021-06-28), see [Setting the allowExternalSenders property](https://docs.microsoft.com/en-us/graph/known-issues#setting-the-allowexternalsenders-property).

### 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 | <p>ExchangeOnlineManagement (>= 3.9.2)<br>RealmJoin.RunbookHelper (>= 0.8.10)</p> |
| Schedulable      | no                                                                                |

### 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 group the runbook acts on. Set by the portal from the selected group.

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

#### Action

Allow lets external senders email the group. Block limits it to internal senders. Query only shows the current state.

| Property            | Value  |
| ------------------- | ------ |
| Required            | false  |
| Default Value       | 0      |
| Type                | Int32  |
| Portal display name | Action |

**Portal options**

| Portal option            | Value |
| ------------------------ | ----- |
| Allow external senders   | 0     |
| Block external senders   | 1     |
| Query current state only | 2     |

[Back to Runbook Reference overview](/automation/runbooks/runbook-references.md)


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://docs.realmjoin.com/automation/runbooks/runbook-references/group/mail/enable-or-disable-external-mail.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.