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：
- 在Exchange中心传输服务器上，运行ADSIEDIT.msc.
- 浏览定位到Configuration->Services->Microsoft Exchange->First Organization->Adminstrative Groups->Exchange Administrative Group ->Servers->server_name->Protocols->SMTP Receive Connector
- 右击Default Receive Connector并切换到Security栏，点击选中Anonymous Logon.
- 在下面的列表中点击选中 Accept Authoritative Domain Sender右边的Deny.
- 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
- 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。
原文地址：http://blog.51cto.com/3032439/2319168