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Exchange 2016 MCSE 70-345 > Transport Services > Flashcards

Flashcards in Transport Services Deck (175)
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1

What Transport Services exist on an Exchange 2016 service?

• Front End Transport Service

• Transport Service

• Mailbox Transport Service
which consists of:
○ Mailbox Transport Submission Service
○ Mailbox Transport Delivery Service

2

What is the Front End Transport service?

• Stateless proxy for inbound, external, SMTP traffic

• Optionally, a stateless proxy for outbound traffic

3

What is the Transport Service?

• handles all SMTP mail flow for the organization

• it performs categorization (determining how to route an e-mail message)

• performs content inspection

• can queue messages

4

What are the Mailbox Transport services?

• Consists of:
○ Mailbox Transport Submission Service
○ Mailbox Transport Delivery Service

• The services that communicate directly with mailbox databases for both inbound and outbound email

5

Which transport services can queue messages?

Only the Transport Service.

(The Front End Transport and Mailbox Transport services cannot.)

6

Which transport services can perform content inspection?

Only the Transport Service

(The Front End Transport and Mailbox Transport services cannot.)

7

What can the Front End Transport service communicate with?

Only the Transport Service, on either the same mailbox server or on another mailbox server.

8

What can the Transport service communicate with?

• Front End Transport Service (on same or other Mailbox servers)

• Transport Service (on other Mailbox servers)

• Mailbox Transport services (on same or other Mailbox servers)

• Edge Transport servers or external SMTP servers for outbound mail

9

What can the Mailbox Transport services communicate with?

• Mailbox databases

• the Transport Service (on same or other Mailbox servers)

10

What is the Transport Pipeline?

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 2016 Mailbox server inside the organization.

11

What is a Routing Destination?

The final destination that Exchange has determined for a message, based on the recipient information.

12

What are possible Routing Destinations?

• a Mailbox database (for internal recipients)

• a Connector (for external recipients)

• a Distribution group expansion server
– if one has been specified for that group. (otherwise, any mailbox server can perform the distribution group expansion)
– When a DG is expanded, it may result in duplication of message for sending to different routing destinations

13

What might cause an e-mail message to be duplicated and sent to different routing destinations?

This can happen, for example, if a distribution group is made up of both internal mailboxes and external contacts.

The message would be duplicated, with one having a routing destination of a mailbox database for the internal recipients, and one with a routing destination of a Send Connector for the external recipients.

14

What is a Delivery Group?

Each Routing Destination has one or more mailbox servers that are responsible for delivering messages to their destination.

Those servers are referred to as a Delivery Group.

15

What are possible Delivery Groups?

• a DAG
– The DAG members are the Delivery Group for any mailboxes that are hosted within that DAG

• Mailbox server(s) within an AD site
– If a mailbox is not hosted in a DAG, then any of the mailbox servers in the same site as the mailbox itself are used as the Delivery Group.

• Source Mailbox servers for a connector
– if a message needs to be sent over a Send Connector, then the source servers for that connector are the Delivery Group.

• an Active Directory site.
– if a hub site has been configured, and it is the least-cost route to the destination, then the mailbox servers in that site are a Delivery Group.

16

How are messages with multiple recipients routed?

For distribution groups:
– The nearest Transport service is used, and the group is expanded to determine routing destinations.

For multiple recipients:
– The first 20 recipients are used to determine the best Transport service to use. Then, that transport service decides what to do from there.

17

How does Exchange route email messages?

The Categorizer calculates the least-cost route to the delivery group for that recipient.

18

What is least-cost routing?

The Active Directory replication topology configures AD Site links with a "cost value."

The lower the "cost," the better the speed or bandwidth of the WAN connection between the two sites.

Exchange looks at these same IP Site Cost Links when calculating the least-cost route between two servers in the same organization.

19

What does "queuing to the point of failure" refer to?

If a site has an outage, then Exchange will try to send messages destined for that site to the closest site and queued until the destination site is online again.

This will only happen if the target mailbox is NOT hosted in a DAG, or if all DAG sites are down.

20

What will happen if a destination mailbox is hosted on a server that is having an outage?

If the mailbox is hosted in a DAG and the DAG member hosting the mailbox is down, then the sending server will try to deliver the message to:

(in order of preference)

• the closets DAG member,

• any DAG member,

• queuing to the point of failure if no DAG members are available

If the mailbox is not hosted by a DAG, then the sending server will simply queue to the point of failure.

21

What is an "Exchange Cost"?

A parameter that can be set on an AD Site Link, which will be used by Exchange to calculate route cost instead of the IP Site Link cost.

Exchange Cost value will override the IP Site Link cost value.

This is useful in situations where the AD topology doesn't match how you want your Exchange routing to behave.

22

How do you configure an Exchange Cost?

Exchange Cost values are assigned to AD Sites Links.

Set-ADSiteLink
"SiteA-SiteB"
-ExchangeCost 5

23

How will a "Hub Site" influence Exchange routing between sites?

When an AD Site has been configured as a Hub Site,

and that site exists on the Least Cost Routing path between two other sites,

then a message will be sent to an exchange server in the Hub site, instead of directly to the destination server.

24

What is the PowerShell command to create a new Hub Site?

To set an AD Site as a Hub Site:

Set-ADSite
"Name of Site"
-HubSiteEnabled:$true

25

What is Shadow Redundancy?

A feature that makes a copy of each e-mail message onto another Mailbox server, to protect the message from failure of a server that is processing the message.

The goal is to improve availability and resilience of e-mail in transit.

26

How does Shadow Redundancy work?

When Front End Transport sends a message to a Transport service, the message will also be copied to another Transport service before the first Transport service acknowledges receipt.

When the Shadow copy has been successfully created, the first mailbox server sends back the acknowledgement to the sending device or server.

27

What is a Shadow Queue?

Part of Shadow Redundancy.

The Shadow Queue is where Shadow copies of e-mail messages are stored on the Shadow server for that message.

28

How is a server selected to copy a message onto for Shadow Redundancy?

If the receiving server is NOT a DAG member:
- a mailbox server in the local directory site is used as the Shadow server.

If the receiving server is a DAG member:
- another DAG member is used as the Shadow server.

If the DAG spans multiple Active Directory sites:
- Shadow Redundancy will try to pick a DAG member in a different site, so you have site resilience for the message.

29

How do you configure Shadow Redundancy?

• It is enabled by default.

• Disabling it is not recommended.

• It is enabled and configured organization-wide. Cannot be configured per-server.

• You can set it to either accept or reject messages if shadow redundancy fails.

30

What happens if a Shadow copy fails to be created?

You have the option to set whether Messages are accepted or rejected if a shadow copy fails to be created.

If you have multiple servers in each AD site, or if servers are members of a DAG, you can set messages to be rejected if the Shadow copy fails to be created, if you want to prioritize resiliency over continued delivery.

In single-server sites/environments, Shadow copies will always fail to be created, so they must be accepted in this setting.