"In-depth Exchange 2013"12 Transport Architecture Part2

This chapter goes through the previous chapter and briefly describes what the four components are responsible for in the entire transport architecture of Exchange Server 2013.

Front End Transport services (the Front End Transport service)

The FET service seems to be minimal in the entire transmission, it is responsible for inbound and outbound SMTP traffic for all clients, FET is the first component that SMTP traffic comes into contact with after the firewall, and other serviced components running on CAS, the FET service does not store any message data. Also does not maintain any queues, and provides essentially stateless client connections (no state information is maintained for client connections). However, the FET generates an SMTP protocol log, so it will still record some data drops.

When you install the Exchange CAS role, a series of default receive connectors are generated for FET use. FETs also provide outbound SMTP services, which are often overlooked by administrators because they are basically concerned with inbound mail. The MBX server drops outbound mail to the FET, so it basically guarantees that all SMTP traffic will only go from the CAS when leaving the current Exchange organization.

Transfer Service (the Transport services)

The transport service in Ex2013 is responsible for most of the functions of the Hub Transport roles of the previous Ex2007 and 2010, and then adds some new improvements to this foundation. such as DLP, such as archiving, such as transmission rules.

The transport service maintains a queue for each internal Exchange mailbox database, and the DAG's features let the transport service not have to figure out which MBX owns the active copy of the database, just know who the target database is. The next mailbox transport delivery service will be responsible for locating the correct database

Mailbox Transport Delivery Service (the Mailbox Transport Delivery service)

When the mailbox transport delivery service tries to post a message for an internal recipient, it first needs to understand the database in which the recipient's mailbox resides. The FET and the transport service perform a simple AD query action beforehand, and then bring an SMTP Messagecontext variable on the message (Exchange 2013 is so, I'm not sure about the other versions.) The Transport delivery service gets this variable, and then it has to figure out which server currently owns the active copy of the database, and if the recipient is in the same DAG as the sender, it will go to the active manager to get the location of the active copy, and if it's the active copy location, It is delivered directly to the database, and if it is another server, it drops the message to its own mailbox transport submission service, which is then dropped by the transport submission service to another server.

If it is in a different DAG, then it determines the location of the target MBX server, using the transport service that SMTP drops to the server, based on the ad information that was said in front of it.

Mailbox Transfer Delivery Service (the Mailbox Transport submission service)

The mailbox Transport delivery service is responsible for retrieving messages from the mailbox using RPC and then submitting them to the transport service via SMTP, which, according to the previous article, puts different messages in a defined location (Outbox, Drafts, and so on), and transmits the post to take the message for the next transfer.

OK, four components are basically described complete, about the four components and the respective ports used, I translated a TechNet blog post a long time ago: Exchange 2013 mail flow, which speaks of something more original rational, you can refer to:

http://sodaxu.blog.51cto.com/8850288/1651613

In the next chapter we'll start talking about connectors, because the content is more, so separate two chapters to talk about the Send connectors and receive connectors.

This article is from the "Castamere Rainy season" blog, be sure to keep this source http://sodaxu.blog.51cto.com/8850288/1674203

"In-depth Exchange 2013"12 Transport Architecture Part2