在缺省情况下Anonymous user权限组有下面的权限：

Ms-Exch-SMTP-Submit

Ms-Exch-SMTP-Accept-Any-Sender

Ms-Exch-SMTP-Accept-Authoritative-Domain-Sender

This permission allows senders that have e-mail addresses in authoritative domains to establish a session to this Receive connector.

Ms-Exch-Accept-Headers-Routing

要阻止别冒充您的域名向您发送邮件，可以使用下面的方法来解决：

方法一：
Exchange 2007-2010如何防止外部连接冒用本域地址向内发邮件？

在缺省情况下Anonymous user权限组有下面的权限：

Ms-Exch-SMTP-Submit

Ms-Exch-SMTP-Accept-Any-Sender

Ms-Exch-SMTP-Accept-Authoritative-Domain-Sender

This permission allows senders that have e-mail addresses in authoritative domains to establish a session to this Receive connector.

Ms-Exch-Accept-Headers-Routing

要阻止别冒充域名发送邮件，可以使用下面的方法来解决：

方法一：

1. 在Exchange中心传输服务器上，运行ADSIEDIT.msc.

2. 浏览定位到Configuration->Services->Microsoft Exchange->First Organization->Adminstrative Groups->Exchange Administrative Group ->Servers->server_name->Protocols->SMTP Receive Connector

3. 右击Default Receive Connector并切换到Security栏，点击选中Anonymous Logon.

4. 在下面的列表中点击选中 Accept Authoritative Domain Sender右边的Deny.

5. 重启Microsoft Transport services服务.

方法二：

1.在PowerShell下输入以下命令：

Get-ReceiveConnector "Default SRV12-01" | Get-ADPermission -user "NT AUTHORITY\Anonymous Logon" | where {$_.ExtendedRights -like "ms-exch-smtp-accept-authoritative-domain-sender"} | Remove-ADPermission

2. 重启Microsoft Transport services服务.

备注：

请将Default SRV12-01替换为您实际的接受连接器的名称，注意是端口为25的那个。