邮件流和传输管道Mail flow and the transport pipeline

在 Exchange Server 中,邮件流通过传输管道进行。In Exchange Server, mail flow occurs through the transport pipeline. 传输管道是一组可协同工作以将所有邮件路由到组织内部 Exchange 邮箱服务器上的传输服务中的分类程序的服务、连接、组件和队列的集合。The transport pipeline is a collection of services, connections, components, and queues that work together to route all messages to the categorizer in the Transport service on an Exchange Mailbox server inside the organization.

有关如何在新的 Exchange 2016 或 Exchange 2019 组织中配置邮件流的信息,请参阅配置邮件流和客户端访问For information about how to configure mail flow in a new Exchange 2016 or Exchange 2019 organization, see Configure mail flow and client access.

了解传输管道Understanding the transport pipeline

传输管道由以下服务组成:The transport pipeline consists of the following services:

  • 邮箱服务器上的前端传输服务:此服务充当 Exchange Server 组织的所有入站和(可选)出站外部 SMTP 流量的无状态代理。Front End Transport service on Mailbox servers: This service acts as a stateless proxy for all inbound and (optionally) outbound external SMTP traffic for the Exchange Server organization. 前端传输服务不检查邮件内容,不与邮箱传输服务通信,也不在本地将任何邮件排入队列。The Front End Transport service doesn't inspect message content, doesn't communicate with the Mailbox Transport service, and doesn't queue any messages locally.

  • 邮箱服务器上的传输服务:此服务实际上与 Exchange server 2010 中的集线器传输服务器角色相同。Transport service on Mailbox servers: This service is virtually identical to the Hub Transport server role in Exchange Server 2010. 传输服务负责处理组织的所有 SMTP 邮件流,并执行邮件分类和邮件内容检查。The Transport service handles all SMTP mail flow for the organization, performs message categorization, and performs message content inspection. 与 Exchange 2010 不同的是,传输服务永远不会与邮箱数据库直接通信。Unlike Exchange 2010, the Transport service never communicates directly with mailbox databases. 此任务现在由邮箱传输服务处理。That task is now handled by the Mailbox Transport service. 传输服务在邮箱传输服务、传输服务、前端传输服务和(视配置而定)边缘传输服务器上的传输服务之间路由邮件。The Transport service routes messages among the Mailbox Transport service, the Transport service, the Front End Transport service, and (depending on your configuration) the Transport service on Edge Transport servers. 本主题稍后将详细介绍邮箱服务器上的传输服务。The Transport service on Mailbox servers is described in more detail later in this topic.

  • 邮箱服务器上的邮箱传输服务:此服务包含两个单独的服务:Mailbox Transport service on Mailbox servers: This service consists of two separate services:

    • 邮箱传输提交服务:此服务使用 Exchange 远程过程调用(RPC)连接到本地邮箱数据库以检索邮件。Mailbox Transport Submission service: This service connects to the local mailbox database using an Exchange remote procedure call (RPC) to retrieve messages. 此服务通过 SMTP 将邮件提交给本地邮箱服务器或其他邮箱服务器上的传输服务。The service submits the messages over SMTP to the Transport service on the local Mailbox server or on other Mailbox servers. 邮箱传输提交服务有权访问与传输服务访问的相同路由拓扑信息。The Mailbox Transport Submission service has access to the same routing topology information as the Transport service.

    • 邮箱传输传递服务:此服务从本地邮箱服务器或其他邮箱服务器上的传输服务接收 SMTP 邮件,并使用 RPC 连接到本地邮箱数据库以传送邮件。Mailbox Transport Delivery service: This service receives SMTP messages from the Transport service on the local Mailbox server or on other Mailbox servers and connects to the local mailbox database using RPC to deliver the messages.

    邮箱传输服务不与前端传输服务、邮箱传输服务或其他邮箱服务器上的邮箱数据库通信。也不会在本地将任何邮件排入队列。The Mailbox Transport service doesn't communicate with the Front End Transport service, the Mailbox Transport service, or mailbox databases on other Mailbox servers. It also doesn't queue any messages locally.

  • 边缘传输服务器上的传输服务:此服务与邮箱服务器上的传输服务非常相似。Transport service on Edge Transport servers: This service is very similar to the Transport service on Mailbox servers. 如果您在外围网络安装了边缘传输服务器,从 Internet 发送或要发送到 Internet 的所有邮件都将通过传输服务边缘传输服务器发送。If you have an Edge Transport server installed in the perimeter network, all mail coming from the Internet or going to the Internet flows through the Transport service Edge Transport server. 此服务会在本主题后面更详细地介绍。This service is described in more detail later in this topic.

下图显示了 Exchange 传输管道中各组件之间的关系。The following diagram shows the relationships among the components in the Exchange transport pipeline.

备注

虽然本主题中的图表显示单个 Exchange 服务器上的组件,但在不同 Exchange 服务器上的这些组件之间也会发生通信。Although the diagrams in this topic show the components on a single Exchange server, communication also occurs between those components on different Exchange servers. 总是在本地 Exchange 服务器上发生的唯一通信是在邮箱传输服务和本地邮箱数据库之间。The only communication that always occurs on the local Exchange server is between the Mailbox Transport service and the local mailbox database.

传输管道概览图

来自外部发件人的邮件如何进入传输管道How messages from external senders enter the transport pipeline

来自 Exchange 组织外部的邮件进入传输管道的方式取决于是否在外围网络中部署了已订阅的边缘传输服务器。The way messages from outside the Exchange organization enter the transport pipeline depends on whether you have a subscribed Edge Transport server deployed in your perimeter network.

入站邮件流(不含边缘传输服务器)Inbound mail flow (no Edge Transport servers)

下面的关系图和列表介绍了仅包含 Exchange 邮箱服务器的入站邮件流。The following diagram and list describe inbound mail flow with only Exchange Mailbox servers.

传输管道中的入站邮件流(没有边缘传输服务器)

  1. 来自组织外部的邮件通过前端传输服务中名为 "默认前端_ <邮箱服务器名称>_" 的默认接收连接器进入传输管道。A message from outside the organization enters the transport pipeline through the default Receive connector named "Default Frontend <Mailbox server name>" in the Front End Transport service.

  2. 此邮件被发送到本地邮箱服务器或其他邮箱服务器上的传输服务。The message is sent to the Transport service on the local Mailbox server or on a different Mailbox server. 传输服务将侦听名为 "默认_ <邮箱服务器名称>_" 的默认接收连接器上的邮件。The Transport service listens for messages on the default Receive connector named "Default <Mailbox server name>".

  3. 邮件从传输服务发送到本地邮箱服务器或其他邮箱服务器上的邮箱传输传递服务。The message is sent from the Transport service to the Mailbox Transport Delivery service on the local Mailbox server or on a different Mailbox server.

  4. 邮箱传输传递服务使用 RPC 将邮件传递到本地邮箱数据库。The Mailbox Transport Delivery service uses RPC to deliver the message to the local mailbox database.

入站邮件流(含边缘传输服务器)Inbound mail flow with Edge Transport servers

下面的关系图和列表展示了包含在外围网络中安装的边缘传输服务器的入站邮件流The following diagram and list describe inbound mail flow with an Edge Transport server installed in the perimeter network

传输管道中的入站邮件流与边缘传输服务器

  1. 来自 Exchange 组织外部的邮件通过边缘传输服务器上的传输服务中名为 "默认内部接收连接器_ <边缘传输服务器名称>_" 的默认接收连接器进入传输管道。A message from outside the Exchange organization enters the transport pipeline through the default Receive connector named "Default internal Receive connector <Edge Transport server name>" in the Transport service on the Edge Transport server.

  2. 在边缘传输服务器上的传输服务中,名为 "EdgeSync-入站到_ <Active directory 站点名称>_" 的默认发送连接器将邮件发送到已订阅的 active directory 站点中的邮箱服务器。In the Transport service on the Edge Transport server, the default Send connector named "EdgeSync - Inbound to <Active Directory site name>" sends the message to a Mailbox server in the subscribed Active Directory site.

  3. 在邮箱服务器上的前端传输服务中,名为 "默认前端_ <邮箱服务器名称>_" 的默认接收连接器接受此邮件。In the Front End Transport service on the Mailbox server, the default Receive connector named "Default Frontend <Mailbox server name>" accepts the message.

  4. 此邮件从前端传输服务发送到本地邮箱服务器或其他邮箱服务器上的传输服务。The message is sent from the Front End Transport service to the Transport service on the local Mailbox server or on a different Mailbox server. 传输服务将侦听名为 "默认_ <邮箱服务器名称>_" 的默认接收连接器上的邮件。The Transport service listens for messages on the default Receive connector named "Default <Mailbox server name>".

  5. 邮件从传输服务发送到本地邮箱服务器上的邮箱传输传递服务,或在不同的邮箱服务器上。The message is sent from the Transport service to the Mailbox Transport Delivery service on the local Mailbox server, or on a different Mailbox server.

  6. 邮箱传输传递服务使用 RPC 将邮件传递到本地邮箱数据库。The Mailbox Transport Delivery service uses RPC to deliver the message to the local mailbox database.

来自内部发件人的邮件如何进入传输管道How messages from internal senders enter the transport pipeline

来自组织内部的 SMTP 邮件可采用下列其中一种方法通过邮箱服务器上的传输服务进入传输管道:SMTP messages from inside the organization enter the transport pipeline through the Transport service on a Mailbox server in one of the following ways:

  • 通过接收连接器。Through a Receive connector.

  • 通过分拣目录或重播目录。From the Pickup directory or the Replay directory.

  • 通过邮箱传输提交服务。From the Mailbox Transport Submission service.

  • 通过代理提交。Through agent submission.

邮件根据路由目标或传递组进行路由。The message is routed based on the routing destination or delivery group.

出站邮件流(不含边缘传输服务器)Outbound mail flow (no Edge Transport servers)

默认情况下,在新的 Exchange 服务器组织中,没有配置为向 Internet 发送邮件的发送连接器。By default, in a new Exchange Server organization, there's no Send connector that's configured to send messages to the Internet. 需要自己创建发送连接器。You need to create the Send connector yourself. 创建后,出站邮件流如以下关系图和列表所述。After you do that, Outbound mail flow occurs as described in the following diagram and list.

传输管道中的出站邮件流(没有边缘传输服务器)

  1. 邮箱传输提交服务使用 RPC 从本地邮箱数据库中检索出站邮件。The Mailbox Transport Submission service uses RPC to retrieve the outbound message from the local mailbox database.

  2. 邮箱传输提交服务使用 SMTP 将邮件发送到本地邮箱服务器或其他邮箱服务器上的传输服务。The Mailbox Transport Submission service uses SMTP to send the message to the Transport service on the local Mailbox server or on a different Mailbox server.

  3. 在传输服务中,名为 "默认_ <邮箱服务器名称>_" 的默认接收连接器接受此邮件。In the Transport service, the default Receive connector named "Default <Mailbox server name>" accepts the message.

  4. 接下来将会发生什么视发送连接器的配置而定:What happens next depends on the configuration of the Send connector:

    • 默认值:传输服务使用你创建的发送连接器将邮件发送到 Internet。Default: The Transport service uses the Send connector you created to send the message to the Internet.

    • 出站代理:传输服务使用您创建的发送连接器将邮件发送到本地邮箱服务器上的前端传输服务或远程邮箱服务器上。Outbound proxy: The Transport service uses the Send connector you created to send the message to the Front End Transport service on the local Mailbox server or on a remote Mailbox server. 在前端传输服务中,名为 "出站代理前端_ <邮箱服务器名称>_" 的默认接收连接器接受此邮件。In the Front End Transport service, the default Receive connector named "Outbound Proxy Frontend <Mailbox server name>" accepts the message. 前端传输服务将邮件发送到 Internet。The Front End Transport services sends the message to the Internet.

出站邮件流(含边缘传输服务器)Outbound mail flow with Edge Transport servers

如果在外围网络中安装了边缘传输服务器,那么出站邮件流永远不会流经前端传输服务。If you have an Edge Transport server installed in the perimeter network, outbound mail never flows through the Front End Transport service. 下面的关系图和列表展示了包含边缘传输服务器的出站邮件流。Outbound mail flow with an Edge Transport server is described in the following diagram and list.

传输管道中的出站邮件流与边缘传输服务器

  1. 邮箱传输提交服务使用 RPC 从本地邮箱数据库中检索出站邮件。The Mailbox Transport Submission service uses RPC to retrieve the outbound message from the local mailbox database.

  2. 邮箱传输提交服务使用 SMTP 将邮件发送到本地邮箱服务器或其他邮箱服务器上的传输服务。The Mailbox Transport Submission service uses SMTP to send the message to the Transport service on the local Mailbox server or on a different Mailbox server.

  3. 在订阅的 Active Directory 站点中的邮箱服务器上的传输服务中,名为 "默认_ <邮箱服务器名称>_" 的默认接收连接器接受此邮件。In the Transport service on a Mailbox server in the subscribed Active Directory site, the default Receive connector named "Default <Mailbox server name>" accepts the message.

  4. 使用隐式和不可见的组织内部发送连接器将邮件发送到边缘传输服务器,后者会在同一组织中的 Exchange 服务器之间自动发送邮件。The message is sent to the Edge Transport server using the implicit and invisible intra-organization Send connector that automatically sends mail between Exchange servers in the same organization.

  5. 在边缘传输服务器上的传输服务中,名为 "默认内部接收连接器_ <边缘传输服务器名称>_" 的默认接收连接器接受此邮件。In the Transport service on the Edge Transport server, the default Receive connector named "Default internal Receive connector <Edge Transport server name>" accepts the message.

  6. 在边缘传输服务器上的传输服务中,名为 "EdgeSync- _ <Active Directory 站点名称> _到 internet" 的默认发送连接器将邮件发送到 internet。In the Transport service on the Edge Transport server, the default Send connector named "EdgeSync - <Active Directory site name> to Internet" sends the message to the Internet.

了解邮箱服务器上的传输服务Understanding the Transport service on Mailbox servers

Exchange 服务器组织中发送或接收的每封邮件都必须在邮箱服务器上的传输服务中进行分类,然后才能对其进行路由和传递。Every message that's sent or received in an Exchange Server organization must be categorized in the Transport service on a Mailbox server before it can be routed and delivered. 对邮件进行分类后,会将其置于传递队列中,以传递到目标邮箱数据库、目标数据库可用性组(DAG)、Active Directory 站点或 Active Directory 林,或者目标域外组织.After a message has been categorized, it's put in a delivery queue for delivery to the destination mailbox database, the destination database availability group (DAG), Active Directory site or Active Directory forest, or to the destination domain outside the organization.

邮箱服务器上的传输服务包含下列组件和过程:The Transport service on a Mailbox server consists of the following components and processes:

  • SMTP 接收:传输服务收到邮件时,将执行邮件内容检查,如果启用,将执行反垃圾邮件检查。SMTP Receive: When messages are received by the Transport service, message content inspection is performed and antispam inspection is performed if is enabled. SMTP 会话包含一系列按特定顺序协同工作的事件,以便在接受邮件之前验证邮件内容。The SMTP session has a series of events that work together in a specific order to validate the contents of a message before it's accepted. 在邮件完全通过 SMTP 接收且未被接收事件或反垃圾邮件代理拒绝后,邮件将放入提交队列中。After a message has passed completely through SMTP Receive and isn't rejected by receive events, or by an antispam agent, it's put in the Submission queue.

  • 提交:提交是将邮件放入提交队列的过程。Submission: Submission is the process of putting messages into the Submission queue. 分类程序一次只选取一封邮件进行分类。The categorizer picks up one message at a time for categorization. 提交过程以三种方式发生:Submission happens in three ways:

    • 对于通过接收连接器的 SMTP 接收。From SMTP Receive through a Receive connector.

    • 通过分拣目录或重播目录。这些目录存在于邮箱服务器和边缘传输服务器上。已复制到分拣目录或重播目录中的格式正确的邮件文件,将直接放入提交队列中。Through the Pickup directory or the Replay directory. These directories exist on Mailbox servers and Edge Transport servers. Correctly formatted message files that are copied into the Pickup directory or the Replay directory are put directly into the Submission queue.

    • 通过传输代理。Through a transport agent.

  • 分类程序:分类程序一次从提交队列中选取一封邮件。Categorizer: The categorizer picks up one message at a time from the Submission queue. 分类程序完成以下步骤:The categorizer completes the following steps:

    • 收件人解析,其中包括顶级寻址、通讯组展开和邮件收件人拆分。Recipient resolution, which includes top-level addressing, distribution group expansion, and message bifurcation.

    • 路由解析。Routing resolution.

    • 内容转换。Content conversion.

      此外,还会应用由组织定义的邮件流规则。Additionally, mail flow rules that the organization defined are applied. 经过分类之后,邮件会被排入按邮件目标划分的传递队列中。After messages have been categorized, they're put into a delivery queue that's based on the destination of the message. 邮件由目标邮箱数据库、DAG、Active Directory 站点、Active Directory 林或外部域的队列进行排队。Messages are queued by the destination mailbox database, DAG, Active Directory site, Active Directory forest, or external domain.

  • SMTP Send:从传输服务路由邮件的方式取决于邮件收件人相对于发生分类的邮箱服务器的位置。SMTP Send: How messages are routed from the Transport service depends on the location of the message recipients relative to the Mailbox server where categorization occurred. 邮件可以路由到以下位置:The message could be routed to one of the following locations:

    • 路由到同一邮箱服务器上的邮箱传输传递服务。To the Mailbox Transport Delivery service on the same Mailbox server.

    • 路由到同一 DAG 中不同邮箱服务器上的邮箱传输传递服务。To the Mailbox Transport Delivery service on a different Mailbox server that's part of the same DAG.

    • 到不同 DAG、Active Directory 站点或 Active Directory 林中的邮箱服务器上的传输服务。To the Transport service on a Mailbox server in a different DAG, Active Directory site, or Active Directory forest.

    • 通过以下服务传递到 Internet:For delivery to the Internet through:

    • 同一邮箱服务器上的发送连接器。A Send connector on the same Mailbox server.

    • 其他邮箱服务器上的传输服务。The Transport service on a different Mailbox server.

    • 同一邮箱服务器或其他邮箱服务器上的前端传输服务(如果已配置出站代理)。The Front End Transport service on the same Mailbox server or a different Mailbox server (if outbound proxy is configured).

    • 外围网络中边缘传输服务器上的传输服务。The Transport service on an Edge Transport server in the perimeter network.

了解边缘传输服务器上的传输服务Understanding the Transport service on Edge Transport servers

边缘传输服务器上的传输服务的组件与邮箱服务器上的传输服务相同。但是,边缘传输服务器上每个处理阶段实际发生的事各不相同。以下列表描述了这些差异。The components of the Transport service on Edge Transport servers are identical to the components of the Transport service on Mailbox servers. However, what actually happens during each stage of processing on Edge Transport servers is different. The differences are described in the following list.

  • SMTP 接收:当将边缘传输服务器订阅到内部 Active Directory 站点时,会自动将名为 "默认<边缘传输服务器名称>" 的默认接收连接器配置为接受来自内部邮箱服务器和 Internet 的邮件。SMTP Receive: When an Edge Transport server is subscribed to an internal Active Directory site, the default Receive connector named "Default <Edge Transport server name>" is automatically configured to accept mail from internal Mailbox servers and from the Internet. 当 Internet 邮件到达边缘传输服务器时,反垃圾邮件代理会筛选连接和邮件内容,并在邮件被接受到组织中时帮助标识发件人和收件人。When Internet messages arrive at the Edge Transport server, antispam agents filter connections and message contents and help identify the sender and the recipient while the message is being accepted into the organization. 默认情况下,会安装并启用反垃圾邮件代理。The antispam agents are installed and enabled by default. 可以使用其他附件筛选和连接筛选功能,但无法使用内置恶意软件筛选功能。Additional attachment filtering and connection filtering features are available, but built-in malware filtering is not. 此外,邮件流规则(也称为传输规则)由边缘规则代理控制。Also, mail flow rules (also known as transport rules) are controlled by the Edge Rule agent. 与邮箱服务器上的传输规则代理相比,边缘传输服务器上只提供了一小部分邮件流规则条件。Compared to the Transport Rule agent on Mailbox servers, only a small subset of mail flow rule conditions are available on Edge Transport servers. 但是,存在与仅在边缘传输服务器上可用的 SMTP 连接相关的唯一邮件流规则操作。But, there are unique mail flow rule actions related to SMTP connections that are available only on Edge Transport servers.

  • 提交:在边缘传输服务器上,邮件通常通过接收连接器进入提交队列。Submission: On an Edge Transport server, messages typically enter the Submission queue through a Receive connector. 但提供分拣目录和重播目录。However, the Pickup directory and the Replay directory are also available.

  • 分类程序:在边缘传输服务器上,分类是直接将邮件放入传递队列以传递给内部或外部收件人的简短过程。Categorizer: On an Edge Transport server, categorization is a short process in which the message is put directly into a delivery queue for delivery to internal or external recipients.

  • SMTP 发送:当将边缘传输服务器订阅到内部 Active Directory 站点时,将自动创建和配置两个发送连接器。SMTP Send: When an Edge Transport server is subscribed to an internal Active Directory site, two Send connectors are automatically created and configured. 一个名为 "EdgeSync <-Active Directory 站点>名称到 internet" 负责将出站邮件发送给 internet 收件人;另一个名为 "EdgeSync-入<站到 Active Directory>站点名称" 负责将入站邮件从 Internet 发送给内部收件人。One named "EdgeSync - <Active Directory site name> to Internet" is responsible for sending outbound mail to Internet recipients; the other named "EdgeSync - Inbound to <Active Directory site name>" is responsible for sending inbound mail from the Internet to internal recipients. 入站邮件发送到订阅的 Active Directory 站点中可用邮箱服务器上的前端传输服务。Inbound mail is sent to the Front End Transport service on an available Mailbox server in the subscribed Active Directory site.