How to check remote domain settings in Exchange Online

Before you start

Use an account in the Organization Management role group: Microsoft lists it for mail flow, and its Remote and Accepted Domains role manages remote domains. Members of View-Only Management can view the configuration without changing it.

A remote domain sets what Exchange Online sends to another domain: out-of-office replies, automatic replies, automatic forwards, delivery and non-delivery reports, and message format. Its settings override what people set in Outlook. Every organisation has Default, which cannot be removed. The examples read the settings and export them; they change nothing.

Option 1

Check remote domain settings with PowerShell

Install the module once, then connect and export every remote domain, Default first.

# Install once, if the module is not already installed.
Install-Module ExchangeOnlineManagement -Scope CurrentUser

$ErrorActionPreference = 'Stop'
Connect-ExchangeOnline -ShowBanner:$false
try {
    $domains = @(Get-RemoteDomain -ResultSize Unlimited)
    if ($domains.Count -eq 0) {
        Write-Output 'No remote domains were returned. Check the role of the account you used.'
    } else {
        $defaultFirst = @{ Expression = { "$($_.DomainName)" -ne '*' } }
        $domains | Sort-Object $defaultFirst, { "$($_.DomainName)" } |
            Select-Object Name, DomainName, AutoForwardEnabled, AutoReplyEnabled,
                AllowedOOFType, DeliveryReportEnabled, NDREnabled,
                MeetingForwardNotificationEnabled, TNEFEnabled, CharacterSet,
                IsInternal, TrustedMailInboundEnabled, TrustedMailOutboundEnabled |
            Export-Csv -Path './remote-domains.csv' -NoTypeInformation -Encoding utf8
        Write-Output "$($domains.Count) remote domains exported."
    }
} finally {
    Disconnect-ExchangeOnline -Confirm:$false
}

The CSV has 1 row for each remote domain. AutoForwardEnabled on Default is the row most people look for first: when it is True, Inbox rules and forwarding set in Outlook on the web can forward mail to any domain without its own entry. The outbound spam policy in Microsoft Defender also controls automatic forwarding outside the organisation, and a block there wins: since 2021 its default setting blocks it in most tenants. TNEFEnabled is blank when the domain follows each person's message format. Add other properties from Set-RemoteDomain to the Select-Object list to keep them.

Check 1 remote domain

Reconnect with Connect-ExchangeOnline, then read 1 remote domain in full. The export above disconnects when it finishes.

# Run while connected to Exchange Online. Default is the entry for every other domain.
Get-RemoteDomain -Identity Default | Format-List DomainName, AutoForwardEnabled,
    AutoReplyEnabled, AllowedOOFType, NDREnabled

Option 2

Review remote domains in the admin centre

1. Open the Exchange admin centre for the correct tenant.
2. Go to Mail flow > Remote domains. The list shows Default and any domain with its own entry.
3. Select Default to read its out-of-office reply types, automatic replies and forwarding, message reporting and text format.
4. Select each other remote domain in turn and compare it with Default.
5. Close each one without saving, and do not choose Delete, so nothing changes.

This suits a look at a tenant you already have open. The admin centre does not show every setting, such as whether a domain's mail is treated as internal, so use PowerShell or a report for those and for a record to keep.

Common questions

Does turning off automatic forwarding on a remote domain stop all forwarding?

No. It blocks forwarding people set up themselves, with Inbox rules or the forwarding option in Outlook on the web. Forwarding an administrator sets on a mailbox, and mail flow rules that forward, are not affected. The forwarded copy is deleted before it is sent, and no error message is returned.

Which setting wins, a domain's own entry or Default?

Where a domain has its own remote domain and a setting conflicts with Default, the domain's own setting applies. Removing a domain's entry puts Default's settings back for that domain; it does not stop mail to it.

How do I find mailboxes that forward mail outside?

Remote domains decide whether forwarding leaves the organisation, not who has it set up. To list the mailboxes with forwarding, see how to find mailbox forwarding in Exchange Online.