Exchange Server 中的邮件路由Mail routing in Exchange Server

您 Exchange 组织中的邮箱服务器上的传输服务的主要任务是,将接收自用户和外部来源的邮件路由到最终目标。路由决策在邮件分类期间做出的。分类程序是传输服务的一个组件,用于处理传入的所有邮件,并根据目标信息确定要对邮件执行的操作。The primary task of the Transport service that exists on Mailbox servers in your Exchange organization is to route messages received from users and external sources to their ultimate destinations. Routing decisions are made during message categorization. The categorizer is a component of the Transport service that processes all incoming messages and determines what to do with the message based on information about their destinations.

Exchange 2016 和 Exchange 2019 中的路由实际上在 Exchange 2013 中保持不变。Routing in Exchange 2016 and Exchange 2019 is virtually unchanged from Exchange 2013. 与 Exchange 2010 相比,路由的显著变化如下:These are the notable changes to routing compared to Exchange 2010:

  • 路由完全了解数据库可用性组(Dag),并且能够在路由决策中使用 DAG 成员身份,即使 DAG 成员位于不同的 Active Directory 站点中也是如此。Routing is fully aware of database availability groups (DAGs), and is able to use DAG membership in routing decisions, even when the DAG members are in different Active Directory sites. 对于不属于 Dag 的邮箱服务器以及与早期版本的 Exchange 的互操作性,在路由决定中仍使用 Active Directory 站点成员资格。For Mailbox servers that don't belong to DAGs and for interoperability with previous versions of Exchange, Active Directory site membership is still used in routing decisions.

  • 传输服务从不直接与邮箱数据库进行通信,而是与本地或远程邮箱服务器上的邮箱传输服务进行通信。只有邮箱传输服务才能与本地邮箱数据库进行通信。当邮箱服务器是 DAG 的成员时,只有保留邮箱数据库主动副本的邮箱服务器上的邮箱传输服务才会接受目标收件人的邮件。The Transport service never communicates directly with a mailbox database. Instead, the Transport service communicates with the Mailbox Transport service locally or on remote Mailbox servers. Only the Mailbox Transport service communicates with the local mailbox database. When the Mailbox server is a member of a DAG, only the Mailbox Transport service on the Mailbox server that holds the active copy of the mailbox database accepts messages for the destination recipient.

  • 远程过程调用 (RPC) 仅供邮箱传输服务使用,用于向本地邮箱数据库发送邮件或接收本地邮箱数据库发送的邮件。当邮箱服务器是 DAG 的成员时,邮箱传输服务仅使用 RPC 与邮箱数据库的主动副本进行本地通信。换句话说,RPC 从不用于跨服务器或跨服务通信。相反,邮箱传输服务和传输服务始终使用 SMTP 进行通信。Remote procedure calls (RPCs) are used only by the Mailbox Transport service to send messages to or receive messages from the local mailbox database. When the Mailbox server is a member of a DAG, the Mailbox Transport service only uses RPCs to communicate locally with the active copies of the mailbox databases. In other words, RPC is never used for cross-server or cross-service communication. Instead, the Mailbox Transport service and the Transport service always communicate using SMTP.

  • Exchange 现在对远程目标使用更精确的队列。Exchange now uses more precise queuing for remote destinations. Exchange 现在不会对远程 Active Directory 站点中的所有目标使用一个队列,而是对 Active Directory 站点中的特定目标(如单个发送连接器)的邮件进行排队。Instead of using one queue for all destinations in a remote Active Directory site, Exchange now queues messages for specific destinations within the Active Directory site, such as individual Send connectors.

  • 链接的连接器不再可用。链接的连接器是链接到发送连接器的接收连接器。接收连接器接收的所有邮件都会自动转发到发送连接器。Linked connectors are no longer available. A linked connector was a Receive connector that was linked to a Send connector. All messages received by the Receive connector were automatically forwarded to the Send connector.

路由组件Routing components

在邮箱服务器上的传输服务收到邮件后,必须对邮件进行分类。When a message is received by the Transport service on a Mailbox server, the message must be categorized. 邮件分类的第一个阶段是收件人解析。The first phase of message categorization is recipient resolution. 在解析了收件人之后,便可以确定最终目标。After the recipient has been resolved, the ultimate destination can be determined. 下一个阶段是路由,用于确定到达最终目标的最佳路径。The next phase, routing, determines how to best reach that destination. 通过使用路由目标传递组的概念,通用化了 Exchange 中的路由,以提高灵活性并降低复杂性。Routing in Exchange is generalized for increased flexibility and decreased complexity by using the concepts of routing destinations and delivery groups.

路由目标Routing destinations

邮件的最终目标称为路由目标The ultimate destination for a message is called a routing destination. 无论 Exchange 组织的复杂度如何,您都会惊奇地发现路由目标非常少。Regardless of the complexity of an Exchange organization, there are surprisingly few routing destinations. 包括:They are:

  • 邮箱数据库:这是 Exchange 组织中具有邮箱的任何收件人的路由目标。A mailbox database: This is the routing destination for any recipient with a mailbox in the Exchange organization. 在 Exchange 2013 或更高版本中,公用文件夹是一种邮箱类型,因此将邮件路由到公用文件夹收件人与将邮件路由到邮箱收件人是一样的。In Exchange 2013 or later, public folders are a type of mailbox, so routing messages to public folder recipients is the same as routing messages to mailbox recipients.

  • 连接器:发送连接器用作 SMTP 邮件的路由目标,具体取决于发送连接器(地址空间、作用域等)的配置。A connector: A Send connector is used as a routing destination for SMTP messages based on the configuration of the Send connector (address spaces, scoped or not, etc.). 同样,传递代理连接器或外部连接器用作非 SMTP 邮件的路由目标。Similarly, a Delivery Agent connector or Foreign connector is used as a routing destination for non-SMTP messages.

  • 通讯组展开服务器:当通讯组具有指定的展开服务器(负责扩展组的成员身份列表的服务器)时,这就是路由目标。A distribution group expansion server: This is the routing destination when a distribution group has a designated expansion server (a server that's responsible for expanding the membership list of the group). 通讯组展开服务器是 Exchange 2013 或更高版本的邮箱服务器或 Exchange 2010 集线器传输服务器。A distribution group expansion server is an Exchange 2013 or later Mailbox server or an Exchange 2010 Hub Transport server.

请注意,虽然旧版 Exchange 中也有这些路由目标,但它们并不被叫做路由目标。Note that these routing destinations existed in previous versions of Exchange, but they weren't called routing destinations.

传递组Delivery groups

一个或多个传输服务器的集合负责将邮件传递到各个路由目标。A collection of one or more transport servers is responsible for delivering mail to each routing destination. 这样的传输服务器集合称为传递组This collection of transport servers is called a delivery group. 由于这些服务器可能是 Exchange 2013 或更高版本的邮箱服务器(传输服务)或 Exchange 2010 集线器传输服务器的混合服务器,因此使用了术语传输服务器The term transport servers is used because the servers could be a mixture of Exchange 2013 or later Mailbox servers (the Transport service) or Exchange 2010 Hub Transport servers. 路由目标和传递组之间的关系如下表所示:The relationship between routing destinations and delivery groups is explained in the following table:

路由目标Routing destination 传递组Delivery group
Exchange 2013 或更高版本的邮箱数据库Exchange 2013 or later mailbox databases Exchange 2013 或更高版本的邮箱服务器。Exchange 2013 or later Mailbox servers.
Exchange 2016 组织中的 exchange 2010 邮箱数据库Exchange 2010 mailbox databases in Exchange 2016 organizations 仅 Exchange 2010 集线器传输服务器。Only Exchange 2010 Hub Transport servers.
连接器Connectors Exchange 2013 或更高版本的邮箱服务器或 Exchange 2010 集线器传输服务器。Exchange 2013 or later Mailbox servers or Exchange 2010 Hub Transport servers.
通讯组展开服务器Distribution group expansion servers Exchange 2013 或更高版本的邮箱服务器或 Exchange 2010 集线器传输服务器。Exchange 2013 or later Mailbox servers or Exchange 2010 Hub Transport servers.

邮件的路由方式取决于源传递组与目标传递组之间的关系:How the message is routed depends on the relationship between the source delivery group and the destination delivery group:

  • 如果源传递组和目标传递组相同,则不需要使用路由决策。路由目标是邮件的下一个跃点。If the source and destination delivery group are the same, no routing decisions are required. The routing destination is the next hop for the message.

  • 如果源传递组位于目标传递组的外部,则需要使用路由决策。邮件会沿最低成本路由路径中继到目标传递组。邮件可能会通过多个传输服务器中继到目标传递组,然后再传递到路由目标,具体视 Exchange 环境的大小和复杂度而定。If the source delivery group is outside the destination delivery group, routing decisions are required. The message is relayed along the least-cost routing path to the destination delivery group. Depending on the size and complexity of the Exchange environment, the message might be relayed through many transport servers to reach the destination delivery group for delivery to the routing destination.

下表总结了 Exchange 2016 中的不同传递组类型。The different types of delivery groups that exist in Exchange 2016 are summarized in the following table.

传递组类型Delivery group type 传递组Delivery group 路由目标Routing destination 注释Comments
可路由 DAGRoutable DAG •属于 Exchange 2019 DAG 的 exchange 2019 邮箱服务器。• Exchange 2019 Mailbox servers that belong to the Exchange 2019 DAG.
•属于 Exchange 2016 DAG 的 exchange 2016 邮箱服务器。• Exchange 2016 Mailbox servers that belong to the Exchange 2016 DAG.
•属于 Exchange 2013 DAG 的 exchange 2013 邮箱服务器。• Exchange 2013 Mailbox servers that belong to the Exchange 2013 DAG.
DAG 中的邮箱数据库Mailbox databases in the DAG 在邮件到达 DAG 中的邮箱服务器后,传输服务会将邮件路由到保留目标邮箱数据库的主动副本的 DAG 成员上的邮箱传输传递服务。然后,邮箱传输传递服务会将邮件传递到本地邮箱数据库。虽然 DAG 可能会包含位于不同 Active Directory 站点中的邮箱服务器,但 DAG 会定义传递组,而不是 Active Directory 站点。After the message arrives at a Mailbox server in the DAG, the Transport service routes the message to the Mailbox Transport Delivery service on the DAG member that holds the active copy of the destination mailbox database. The Mailbox Transport Delivery service then delivers the message to the local mailbox database. Although a DAG might contain Mailbox servers located in different Active Directory sites, the DAG defines the delivery group, not the Active Directory site.
邮箱传递组(Exchange 2013 或更高版本)Mailbox delivery group (Exchange 2013 or later) Active Directory 站点中的 Exchange 2013 或更高版本的邮箱服务器。Exchange 2013 or later Mailbox servers in the Active Directory site. 不属于 DAG 的 Active Directory 站点中的 Exchange 2013 或更高版本服务器上的邮箱数据库。Mailbox databases on Exchange 2013 or later servers in the Active Directory site that don't belong to a DAG. 位于不属于 DAG 的服务器上的邮箱数据库由同一 Active Directory 站点中的邮箱服务器上的传输服务提供服务。Mailbox databases located on servers that don't belong to a DAG are serviced by the Transport service on Mailbox servers in the same Active Directory site.
邮件到达 Active Directory 站点中的邮箱服务器后,传输服务使用 SMTP 将邮件传输到包含邮箱数据库的邮箱服务器上的邮箱传输传递服务。After the message arrives on an Mailbox server in the Active Directory site, the Transport service uses SMTP to transfer the message to the Mailbox Transport Delivery service on the Mailbox server that holds the mailbox database. 然后,邮箱传输传递服务会使用 RPC 将邮件传递到本地邮箱数据库。The Mailbox Transport Delivery service then delivers the message to the local mailbox database using RPC.
也就是说,不同版本的 Exchange 均支持以下邮件传递路径:In other words, the following mail delivery paths are supported between the different versions of Exchange:
• Exchange 2019 传输服务到 exchange 2016 邮箱传输传递服务到 Exchange 2016 邮箱数据库。• Exchange 2019 Transport service to Exchange 2016 Mailbox Transport Delivery service to Exchange 2016 mailbox database.
• Exchange 2019 传输服务到 exchange 2013 邮箱传输传递服务到 Exchange 2013 邮箱数据库。• Exchange 2019 Transport service to Exchange 2013 Mailbox Transport Delivery service to Exchange 2013 mailbox database.
• Exchange 2016 传输服务到 exchange 2019 邮箱传输传递服务到 Exchange 2019 邮箱数据库。• Exchange 2016 Transport service to Exchange 2019 Mailbox Transport Delivery service to Exchange 2019 mailbox database.
• Exchange 2016 传输服务到 exchange 2013 邮箱传输传递服务到 Exchange 2013 邮箱数据库。• Exchange 2016 Transport service to Exchange 2013 Mailbox Transport Delivery service to Exchange 2013 mailbox database.
• Exchange 2013 传输服务到 exchange 2019 邮箱传输传递服务到 Exchange 2019 邮箱数据库。• Exchange 2013 Transport service to Exchange 2019 Mailbox Transport Delivery service to Exchange 2019 mailbox database.
• Exchange 2013 传输服务到 exchange 2016 邮箱传输传递服务到 Exchange 2016 邮箱数据库。• Exchange 2013 Transport service to Exchange 2016 Mailbox Transport Delivery service to Exchange 2016 mailbox database.
邮箱传递组 (Exchange 2010)Mailbox delivery group (Exchange 2010) Active Directory 站点中的 Exchange 2010 集线器传输服务器。Exchange 2010 Hub Transport servers in the Active Directory site. Active Directory 站点中的 Exchange 2010 邮箱服务器上的邮箱数据库。Mailbox databases on Exchange 2010 Mailbox servers in the Active Directory site. Exchange 2010 邮箱服务器上的邮箱数据库由同一 Active Directory 站点中的 Exchange 2010 集线器传输服务器提供服务。Mailbox databases located on Exchange 2010 Mailbox servers are serviced by the Exchange 2010 Hub Transport servers in the same Active Directory site.
在邮件到达 Active Directory 站点中的随机 Exchange 2010 集线器传输服务器之后,集线器传输服务器上的存储驱动程序会使用 RPC 将邮件写入邮箱数据库。After the message arrives at a random Exchange 2010 Hub Transport server in the Active Directory site, the store driver on the Hub Transport server uses RPC to write the message to the mailbox database.
连接器源服务器Connector source server 为连接器定义为源传输服务器的任何 Exchange 2013 或更高版本的邮箱服务器或 Exchange 2010 集线器传输服务器的混合。A mixture of any Exchange 2013 or later Mailbox servers or Exchange 2010 Hub Transport servers that are defined as source transport servers for the connector. 发送连接器、传递代理连接器或外部连接器。A Send connector, Delivery Agent connector, or Foreign connector. 如果连接器已限定范围(即仅限同一 Active Directory 站点中的传输服务器使用),那么只有此站点中的其他传输服务器会注意到连接器,并能使用连接器路由邮件。If the connector is scoped (that is, restricted to transport servers in the same Active Directory site), then only other transport servers in that site are aware of the connector, and can use the connector to route mail.
如果连接器未限定范围,那么整个 Active Directory 林中的所有传输服务器都会注意到连接器,并能使用连接器路由邮件。If the connector isn't scoped, then all transport servers in the entire Active Directory forest are aware of the connector, and can use the connector to route mail.
服务器列表Server list 定义为通讯组展开服务器的 Exchange 2013 或更高版本的邮箱服务器或 Exchange 2010 集线器传输服务器。The Exchange 2013 or later Mailbox server or Exchange 2010 Hub Transport server that's defined as the expansion server for the distribution group. 通讯组展开服务器。The distribution group expansion server. none
AD 站点AD site Exchange 2013 或更高版本的邮箱服务器或 Exchange 2010 集线器传输服务器的任意组合,它们存在于:Any mixture of Exchange 2013 or later Mailbox servers or Exchange 2010 Hub Transport servers that exist in:
•配置为中心网站的 Active Directory 站点。• Active Directory sites that are configured as hub sites.
•已订阅边缘传输服务器的 Active Directory 站点。• Active Directory sites that have subscribed Edge Transport servers.
无。None. 邮件必须经过 Active Directory 站点到达实际的路由目标。The message must travel through the Active Directory site on the way to the actual routing destination. 此传递组类型是 Exchange 2013 或更高版本中仍使用延迟扇出的唯一路由方案。This delivery group type is the only routing scenario in Exchange 2013 or later where delayed fan-out is still used. 当多个路由目标共享最低成本路由路径的一部分时,延迟扇出会尝试减少邮件传输数。Delayed fan-out attempts to reduce the number of message transmissions when multiple routing destinations share part of the least-cost routing path.
只有当邮件的最低成本路由路径上存在 Active Directory 站点时,才会使用中心站点。Hub sites are used only if the Active Directory site exists along the least-cost routing path for the message. 适用于边缘传输服务器的 br/>,订阅的 Active Directory 站点中的任何邮箱服务器上的传输服务都可以将邮件发送到边缘传输服务器,而不管该服务器是否参与 EdgeSync 同步。br/> For Edge Transport servers, the Transport service on any Mailbox server in the subscribed Active Directory site is able to send messages to the Edge Transport server, regardless of whether that server participates in EdgeSync synchronization. 有关详细信息,请参阅边缘传输服务器For more information, see Edge Transport servers.

备注

传递组成员身份并不相互排斥。Delivery group membership isn't mutually exclusive. 例如,DAG 成员的邮箱服务器也可以是发送连接器的源传输服务器。For example, a Mailbox server that's a member of a DAG can also be the source transport server of a Send connector. 此邮箱服务器既属于 DAG 中邮箱数据库的可路由 DAG 传递组,也属于发送连接器的连接器源服务器传递组。The Mailbox server belongs to the routable DAG delivery group for the mailbox databases in the DAG, and the connector source server delivery group for the Send connector.

队列Queues

从发送传输服务器的角度来说,每个邮件传递队列代表特定邮件的目标。在传输服务选择邮件的目标后,目标会作为 NextHopSolutionKey 属性在收件人上进行标记。如果将一封邮件发送给多个收件人,则每个收件人都具有 NextHopSolutionKey 属性。接收传输服务器还执行邮件分类,并将邮件排入队列以供传递。在邮件排入队列后,您可以检查特定队列的传递类型,以确定邮件在到达下一个跃点目标时是否将被再次中继。 NextHopSolutionKey 属性的每个唯一值均对应于单独的邮件传递队列。From the perspective of the sending transport server, each message delivery queue represents the destination for a particular message. When the Transport service selects the destination for a message, the destination is stamped on the recipient as the NextHopSolutionKey attribute. If a single message is sent to more than one recipient, each recipient has the NextHopSolutionKey attribute. The receiving transport server also performs message categorization and queues the message for delivery. After a message is queued, you can examine the delivery type for a particular queue to determine whether a message will be relayed again when it reaches the next hop destination. Every unique value of the NextHopSolutionKey attribute corresponds to a separate message delivery queue.

有关详细信息,请参阅 NextHopSolutionKeyFor more information, see NextHopSolutionKey.

路由邮件Routing messages

当邮件需要传递到远程传递组时,必须为邮件确定路由路径。When a message needs to be delivered to a remote delivery group, a routing path must be determined for the message. Exchange 使用以下逻辑选择邮件的路由路径。Exchange uses the following logic to select the routing path for a message. 此逻辑基本上与 Exchange 2010 相同:This logic is basically unchanged from Exchange 2010:

  1. 通过将到达目标必须经过的 IP 站点链接的成本相加,计算出最低成本路由路径。如果目标是连接器,则将为地址空间分配的开销加到通向所选连接器的开销中。如果有多个可能的路由路径,则使用总成本最低的路由路径。Calculate the least-cost routing path by adding the cost of the IP site links that must be traversed to reach the destination. If the destination is a connector, the cost assigned to the address space is added to the cost to reach the selected connector. If multiple routing paths are possible, the routing path with the lowest aggregate cost is used.

    注意:连接器上的大小限制是这里的一个因素。Note: Size limits on connectors are a factor here. 配置为邮件大小限制小于邮件大小的连接器将从考虑中消失。Connectors that are configured with message sizes limits smaller than the size of the message are eliminated from consideration. 有关详细信息,请参阅外部邮件路由中的连接器选择For more information, see Connector selection in external message routing.

  2. 如果多个路由路径的总开销相同,将计算每个路径中的跃点数,并使用跃点数最少的路由路径。If more than one routing path has the same aggregate cost, the number of hops in each path is evaluated and the routing path with the least number of hops is used.

  3. 如果仍有多个可用的路由路径,则会考虑分配给目标前面的 Active Directory 站点的名称。在所使用的路由路径中,最接近目标的 Active Directory 站点的字母数字顺序最小。如果所有被评估的路由路径中与目标最接近的站点为同一个,则考虑前一个站点名称。If more than one routing path is still available, the name assigned to the Active Directory sites before the destination is considered. The routing path where the Active Directory site nearest the destination is lowest in alphanumeric order is used. If the site nearest the destination is the same for all routing paths being evaluated, an earlier site name is considered.

在 Exchange 2010 中,每个邮件收件人只与一个 Active Directory 站点相关联,从源 Active Directory 站点到目标站点只有一个成本最低路由路径。In Exchange 2010, each message recipient is associated with only one Active Directory site, and there is only one least cost routing from the source Active Directory site to the destination site. 在 Exchange 2013 或更高版本中,传递组可以跨越多个 Active Directory 站点,并且可能会有多个最小开销的路由路径到这些站点。In Exchange 2013 or later, a delivery group might span multiple Active Directory sites, and there might be multiple least-cost routing paths to those sites. Exchange 将目标传递组中的单个 Active Directory 站点指定为主站点Exchange designates a single Active Directory site in the destination delivery group as the primary site. 主站点是指根据前面介绍的路由逻辑得出的最接近 Active Directory 站点。The primary site is closest Active Directory site based on the routing logic described earlier. 若要在传递组之间成功路由邮件,Exchange 需要考虑以下问题:To successfully route messages between delivery groups, Exchange takes the following issues into consideration:

  • 在开销最低的路由路径上存在一个或多个中心站点:如果主站点的成本最低的路由路径中包含任何中心站点,则必须通过中心站点路由邮件。The presence of one or more hub sites along the least-cost routing path: If the least-cost routing path to the primary site contains any hub sites, the message must be routed through the hub sites. 会选择沿成本最低路由路径的最近中心站点作为类型 AD site 的新传递组,其中包括中心站点中的所有传输服务器。The closest hub site along the least-cost routing path is selected as a new delivery group of the type AD site, which includes all transport servers in the hub site. 在邮件经过中心站点之后,会继续沿成本最低路由路径路由邮件。After the message traverses the hub site, routing of the message along the least-cost routing path continues. 如果主站点碰巧就是中心站点,则出于以下原因仍将此主站点视为中心站点:If the primary site happens to be a hub site, the primary site is still considered a hub site for the following reasons:

    • 如果目标传递组跨多个 Active Directory 站点,则源服务器只应尝试连接到中心站点内的服务器。If the destination delivery group spans multiple Active Directory sites, the source server should only attempt to connect to the servers in the hub site.

    • 首选中心站点内属于目标传递组的服务器。The servers in the hub site that belong to the target delivery group are preferred.

      与旧版 Exchange 中一样,不在指向主站点的成本最低路由路径中的中心站点会遭到忽略。As in previous version of Exchange, hub sites that aren't in the least-cost routing path to the primary site are ignored.

  • 要在目标路由组中选择的目标 Exchange 服务器:当目标传递组跨多个 Active Directory 站点时,传递组中特定服务器的路由路径可能具有不同的开销。The target Exchange server to select in the destination routing group: When the destination delivery group spans multiple Active Directory sites, the routing path to specific servers within the delivery group might have different costs. 系统会根据成本最低路由路径选择位于最接近 Active Directory 站点中的服务器作为传递组的目标服务器,并会选择这些服务器所处的 Active Directory 站点作为主站点。Servers located in the closest Active Directory site are selected as the target servers for the delivery group based on the least-cost routing path, and the Active Directory site those servers are in is selected as the primary site.

  • 当对目标路由组中的所有服务器的连接尝试失败时的回退选项:如果目标传递组跨多个 Active directory 站点,则第一个回退选项是其他 Active directory 站点中目标传递组中的所有其他服务器,这些服务器未被选作目标服务器。Fallback options when connection attempts to all servers in the destination routing group fail: If the destination delivery group spans multiple Active Directory sites, the first fallback option is all other servers in the destination delivery group in other Active Directory sites that aren't selected as target servers. 服务器选择依据为指向其他 Active Directory 站点的最低成本路由路径。Server selection is based on the least-cost routing path to the other Active Directory sites. 如果目标传递组在本地 Active Directory 站点中有任何服务器,则不存在其他任何回退选项,因为邮件已尽可能接近于目标路由目标。If the destination delivery group has any servers in the local Active Directory site, there are no other fallback options because the message is already as close to the target routing destination as possible. 如果目标传递组在远程 Active Directory 站点中有服务器,则回退选项是尝试连接到主站点中的其他所有服务器。If the destination delivery group has servers in remote Active Directory sites, the option is to try to connect to all other servers in the primary site. 如果失败,则使用指向主站点的成本最低路由路径中的回退路径。If that fails, a backoff path in the least-cost routing path to the primary site is used. 在建立连接之前,Exchange 会尝试通过跳转(通过跃点)将邮件传递到接近目标的位置,并将开销最小的路由路径。Exchange tries to deliver the message as close to the destination as possible by backing off, hop by hop, along the least-cost routing path until a connection is made.

Routing messages between Active Directory sitesRouting messages between Active Directory sites

Exchange 在 Active Directory 站点之间路由邮件的方式实际上与 Exchange 2010 相同。The way that Exchange routes messages between Active Directory sites is virtually the same as Exchange 2010. 有关详细信息,请参阅在 Active Directory 站点之间路由邮件For more information, see Route Mail Between Active Directory Sites.

在邮箱服务器上的前端传输服务中路由Routing in the Front End Transport service on Mailbox servers

前端传输服务可作为 Exchange 组织的所有入站和(可选)出站外部 SMTP 流量的无状态代理。对于待发邮件,只有在专门进行配置的情况下,传输服务才会与前端传输服务进行通信。有关详细信息,请参阅Configure Send connectors to proxy outbound mailThe Front End Transport service acts as a stateless proxy for all inbound and (optionally) outbound external SMTP traffic for the Exchange organization. For outgoing messages, the Transport service communicates with the Front End Transport service only when it's specifically configured to do so. For more information, see Configure Send connectors to proxy outbound mail.

对于传入的邮件,前端传输服务必须快速找到一个正常运行的传输服务来接收邮件传输,无论收件人的数量或类型如何。如果未能这样做,则会导致发送服务器认为电子邮件服务不可用。与传输服务一样,前端传输服务根据 Active Directory 中的信息加载路由表,并使用传递组确定如何路由邮件。不同的是,前端传输服务使用的路由表具有以下独特特征:For incoming messages, the Front End Transport service must quickly find a single, healthy Transport service to receive the message transmission, regardless of the number or type of recipients. Failure to do so results in the email service being perceived as unavailable by the sending server. Like the Transport service, the Front End Transport service loads routing tables based on information from Active Directory, and uses delivery groups to determine how to route messages. However, the routing tables used by the Front End Transport service have the following unique characteristics:

  • 前端传输服务永远不会被视为传递组的成员,即使邮箱服务器和客户端访问服务器安装在同一物理服务器上(在 Exchange 2016 或更高版本中总是如此)也是如此)。The Front End Transport service is never considered a member of a delivery group, even when the Mailbox server and the Client access server are installed on the same physical server (which is always the case in Exchange 2016 or later). 这会强制前端传输服务只与运输服务进行通信。This forces the Front End Transport service to communicate only with the Transport service.

  • 路由表不包含任何发送连接器路由。The routing tables don't contain any Send connector routes.

  • 路由表包含本地 Active Directory 站点中邮箱服务器的特殊列表,以供快速故障转移时使用。The routing tables contain a special list of Mailbox servers in the local Active Directory site for fast fail-over purposes.

前端传输服务中的路由将邮件收件人解析为邮箱数据库。前端传输服务使用的邮箱服务器的列表基于邮件收件人的邮箱数据库。请注意,可能没有任何收件人具有邮箱(例如在收件人为通讯组或邮件用户时)。对于每个邮箱数据库,前端传输服务会查找传递组和关联路由信息。前端传输服务使用的传递组为:Routing in the Front End Transport service resolves message recipients to mailbox databases. The list of Mailbox servers used by the Front End Transport service is based on the mailbox databases of the message recipients. Note that it's possible that none of the recipients have mailboxes, for example, if the recipient is a distribution group or a mail user. For each mailbox database, the Front End Transport service looks up the delivery group and the associated routing information. The delivery groups used by the Front End Transport service are:

  • 可路由 DAGRoutable DAG

  • 邮箱传递组Mailbox delivery group

  • AD 站点AD site

根据收件人的数量和类型,前端传输服务执行以下操作之一:Depending on the number and type of recipients, the Front End Transport service performs one of the following actions:

  • 对于只有一个邮箱收件人的邮件,选择目标传递组中的邮箱服务器,然后根据 Active Directory 站点的邻近程度将此邮箱服务器设置为优先服务器。将邮件路由到收件人可能涉及通过中心站点路由邮件。For messages with a single mailbox recipient, select a Mailbox server in the target delivery group, and give preference to the Mailbox server based on the proximity of the Active Directory site. Routing the message to the recipient might involve routing the message through a hub site.

  • 对于具有多个邮箱收件人的邮件,使用前 20 个收件人,以便根据 Active Directory 站点的邻近程度选择最接近的传递组中的邮箱服务器。请注意,由于前端传输中不会发生邮件收件人拆分,因此无论邮件具有多少收件人,最终只会选择一个邮箱服务器。For messages with multiple mailbox recipients, use the first 20 recipients to select a Mailbox server in the closest delivery group, based on the proximity of the Active Directory site. Note that message bifurcation doesn't occur in Front End Transport, so only one Mailbox server is ultimately selected, regardless of number of recipients in a message.

  • 如果邮件没有邮箱收件人,则在本地 Active Directory 站点中随机选择一个邮箱服务器。If the message has no mailbox recipients, select a random Mailbox server in the local Active Directory site.

在邮箱服务器上的邮箱传输服务中路由Routing in the Mailbox Transport service on Mailbox servers

邮箱传输服务包含两个单独服务:邮箱传输提交服务和邮箱传输传递服务。邮箱传输传递服务从传输服务接收 SMTP 邮件,并使用 RPC 连接到本地邮箱数据库以传递邮件。邮箱传输提交服务使用 RPC 连接到本地邮箱数据库以检索邮件,并通过 SMTP 将邮件提交给传输服务。邮箱传输服务既无状态,也不使用邮件传递队列。The Mailbox Transport service consists of two separate services: the Mailbox Transport Submission service and Mailbox Transport Delivery service. The Mailbox Transport Delivery service receives SMTP messages from the Transport service, and connects to the local mailbox database by using RPC to deliver the message. The Mailbox Transport Submission service connects to the local mailbox database by using RPC to retrieve messages, and submits the messages over SMTP to the Transport service. The Mailbox Transport service is stateless, and doesn't use message delivery queues.

与传输服务一样,邮箱传输服务根据 Active Directory 中的信息加载路由表,并使用传递组确定如何路由邮件。不同的是,邮箱传输服务具有以下独特的路由特征:Like the Transport service, the Mailbox Transport service loads routing tables based on information from Active Directory, and uses delivery groups to determine how to route messages. However, there are routing aspects that are unique to the Mailbox Transport service:

  • 因为传输服务和邮箱传输服务位于相同的邮箱服务器上,所以邮箱传输服务始终与邮箱服务器同属一个传递组。此传递组称为本地传递组Because the Transport service and the Mailbox Transport service exist on the same Mailbox server, the Mailbox Transport service always belongs to the same delivery group as the Mailbox server. This delivery group is referred to as the local delivery group.

  • 邮箱传输提交服务不会自动将邮件发送给本地邮箱服务器上或自己的本地传递组中的其他邮箱服务器上的传输服务。邮箱传输提交服务可以访问与传输服务相同的路由拓扑信息,因此邮箱传输提交服务可以将邮件发送到传递组外部的邮箱服务器上的传输服务。本地传递组中的邮箱服务器用作回退选项,并用于传递给非邮箱收件人。The Mailbox Transport Submission service doesn't automatically send messages to the Transport service on the local Mailbox server or on other Mailbox servers in its own local delivery group. The Mailbox Transport Submission service has access to the same routing topology information as the Transport service, so the Mailbox Transport submission service can send messages to the Transport service on Mailbox servers outside the delivery group. The Mailbox servers in the local delivery group are used as fallback options, and for delivery to non-mailbox recipients.

  • 邮箱传输服务只与邮箱服务器上的传输服务进行通信。The Mailbox Transport service only communicates with the Transport service on Mailbox servers.

  • 邮箱传输服务只与本地邮箱数据库进行通信,从不与其他邮箱服务器上的邮箱数据库进行通信。The Mailbox Transport service only communicates with local mailbox databases. The Mailbox Transport service never communicates with mailbox databases on other Mailbox servers.

当用户从其邮箱发送邮件时,邮箱传输提交服务会将邮件收件人解析为邮箱数据库。邮箱传输提交服务使用的邮箱服务器的列表基于邮件收件人的邮箱数据库。请注意,可能没有任何收件人具有邮箱(例如在收件人为通讯组或邮件用户时)。对于每个邮箱数据库,邮箱传输提交服务会查找传递组和关联路由信息。邮箱传输提交服务使用的传递组为:When a user sends a message from their mailbox, the Mailbox Transport Submission service resolves the message recipients to mailbox databases. The list of Mailbox servers used by the Mailbox Transport Submission service is based on the mailbox databases of the message recipients. Note that it's possible that none of the recipients have mailboxes, for example, if the recipient is a distribution group or a mail user. For each mailbox database, the Mailbox Transport Submission service looks up the delivery group and the associated routing information. The delivery groups used by the Mailbox Transport Submission service are:

  • 可路由 DAGRoutable DAG

  • 邮箱传递组Mailbox delivery group

  • AD 站点AD site

根据收件人的数量和类型,邮箱传输提交服务执行以下操作之一:Depending on the number and type of recipients, the Mailbox Transport Submission service performs one of the following actions:

  • 对于只有一个邮箱收件人的邮件,选择目标传递组中的邮箱服务器,然后根据 Active Directory 站点的邻近程度将此邮箱服务器设置为优先服务器。将邮件路由到收件人可能涉及通过中心站点路由邮件。For messages with a single mailbox recipient, select a Mailbox server in the target delivery group, and give preference to the Mailbox server based on the proximity of the Active Directory site. Routing the message to the recipient might involve routing the message through a hub site.

  • 对于具有多个邮箱收件人的邮件,使用前 20 个收件人,以便根据 Active Directory 站点的邻近程度选择最接近的传递组中的邮箱服务器。For messages with multiple mailbox recipients, use the first 20 recipients to select a Mailbox server in the closest delivery group, based on the proximity of the Active Directory site.

  • 如果邮件没有邮箱收件人,则在本地传递组中选择邮箱服务器。If the message has no mailbox recipients, select a Mailbox server in the local delivery group.

当邮箱传输传递服务从传输服务接收邮件时,它会接受或拒绝传递给本地邮箱数据库的邮件。如果收件人驻留在本地邮箱数据库的主动副本中,则邮箱传输传递服务可以传递邮件。但是如果收件人不驻留在本地邮箱数据库的主动副本中,则邮箱传输传递服务无法传递邮件,并且必须向传输服务提供未送达响应。例如,如果邮箱数据库的主动副本最近移动到另一台服务器,则传输服务可能错误地将邮件传输到现在保存邮箱数据库非主动副本的邮箱服务器。邮箱传输传递服务返回给传输服务的未送达响应包括:When the Mailbox Transport Delivery service receives a message from the Transport service, it accepts or rejects the message for delivery to a local mailbox database. The Mailbox Transport Delivery service can deliver the message if the recipient resides in an active copy of a local mailbox database. But, if the recipient doesn't reside in an active copy of a local mailbox database, the Mailbox Transport Delivery service can't deliver the message, and must provide a non-delivery response to the Transport service. For example, if the active copy of the mailbox database recently moved to another server, the Transport service might erroneously transmit a message to a Mailbox server that now holds an inactive copy of the mailbox database. The non-delivery responses that the Mailbox Transport Delivery service returns to the Transport service include:

  • 重试传递Retry delivery

  • 生成未送达报告 (NDR)(亦称为"传递状态通知 (DSN)"或"退回邮件")Generate an NDR (also known as a non-delivery report, delivery status notification, DSN, or bounce message)

  • 重新路由邮件Reroute the message

在边缘传输服务器上的传输服务中路由Routing in the Transport service on Edge Transport servers

边缘传输服务器中的传输服务可向所有 Internet 邮件流提供 SMTP 中继和智能主机服务。来自 Internet 的邮件和发往 Internet 的邮件都存储在边缘传输服务器上的邮件传递队列中。队列与外部域或发送连接器相对应。有关详细信息,请参阅 NextHopSolutionKeyThe Transport service on Edge Transport servers provides SMTP relay and smart host services for all Internet mail flow. Messages that come and go from the Internet are stored in message delivery queues on the Edge Transport server. The queues correspond to external domains or Send connectors. For more information, see NextHopSolutionKey.

通常情况下,当您在外围网络中安装边缘传输服务器时,会将边缘传输服务器订阅到 Active Directory 站点。Active Directory 站点包含的邮箱服务器既会将邮件中继到边缘传输服务器,也会中继来自边缘传输服务器的邮件。边缘订阅流程为边缘传输服务器创建了 Active Directory 站点成员资格附属关系。借助站点附属关系,Active Directory 站点中的邮箱服务器可以将邮件中继到边缘传输服务器,而无需配置显式发送连接器。Typically, when you install an Edge Transport server in your perimeter network, you subscribe the Edge Transport server to an Active Directory site. The Active Directory site contains the Mailbox servers that relay messages to and from the Edge Transport server. The Edge Subscription process creates an Active Directory site membership affiliation for the Edge Transport server. The site affiliation enables the Mailbox servers in the Active Directory site to relay messages to the Edge Transport server without having to configure explicit Send connectors.

在多个 Active Directory 站点中具有 Exchange 服务器的组织中,从内部收件人到外部收件人的出站邮件会先路由到订阅的 Active Directory 站点。In organizations that have Exchange servers in multiple Active Directory sites, outbound mail from internal recipients to external recipients is first routed to the subscribed Active Directory site. 目标 Active Directory 站点中的传输服务器为传递组。Transport servers in the target Active Directory site are the delivery group. 路由目标为订阅的 Active Directory 站点中任意邮箱服务器上的传输服务中的组织内发送连接器。The routing destination is the intra-organization Send connector in the Transport service on any of the Mailbox servers in the subscribed Active Directory site. 组织内发送连接器是每个邮箱服务器上的传输服务中的特殊发送连接器。The intra-organization Send connector is special Send connector that exists in the Transport service on every Mailbox server. 此发送连接器是隐式创建的,因此并不可见,也不需要管理,可用于在 Exchange 服务器之间中继邮件。This Send connector is implicitly created, invisible, requires no management, and is used to relay messages between Exchange servers.

若要详细了解如何将邮件路由到边缘传输服务器,以及路由来自边缘服务器的邮件,请参阅Mail flow and the transport pipelineFor more information about how mail is routed to and from Edge Transport servers, see Mail flow and the transport pipeline.