Tài liệu Module 7: Configuring IIS to Provide E-Mail Support doc

Configuring Support for the SMTP Service Explain that you designate an SMTP virtual server by its Internet Protocol IP address and Transmission Control Protocol TCP port number.. Overvie

Contents

Overview 1

Introduction to the SMTP Service 2

Configuring Support for the SMTP Service 4

Configuring Security for the SMTP Service 19

Lab A: Configuring and Testing the SMTP

Service 35

Review 45

Module 7: Configuring IIS to Provide E-Mail Support

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Instructor Notes

This module provides students with the knowledge and skills to provide e-mail support in Microsoft® Internet Information Services (IIS) 5.0

After completing this module, students will be able to:

Explain what the Simple Mail Transfer Protocol (SMTP) service is and how

it works

Configure support for the SMTP service

Control e-mail messages for the SMTP service

Configure security for the SMTP service

Manage the SMTP service

Materials and Preparation

This section provides the materials and preparation tasks that you need to teach this module

Required Materials

To teach this module, you need the Microsoft PowerPoint® file 2295A_07.ppt

Preparation Tasks

To prepare for this module, you should:

Read all of the materials for this module

Complete the labs

Presentation:

45 Minutes

Lab:

30 Minutes

Module Strategy

Use the following strategy to present this module:

Introduction to the SMTP Service Explain that SMTP is the Internet standard for e-mail message delivery Describe how the SMTP service works in IIS, and how the SMTP server sends and receives e-mail messages Explain that, if they did not enable the SMTP service during Microsoft Windows® 2000 installation, they can

enable it by using Add/Remove Programs in Control Panel

Configuring Support for the SMTP Service Explain that you designate an SMTP virtual server by its Internet Protocol (IP) address and Transmission Control Protocol (TCP) port number Discuss local and remote domains Discuss alias domains, and explain that they are just another name for a local domain and cannot be configured Discuss how remote domains are used to override the SMTP virtual server’s default settings for sending messages Display the SMTP folders and discuss how each is used

Controlling E-Mail Messages Explain the different settings that are available to control the flow of messages to and from the SMTP server Discuss that, although these settings may improve server performance, they also have trade-offs that need to be considered Diagram a situation that uses a smart host

Configuring Security for the SMTP Service Discuss the various security risks to an SMTP server, and explain the corresponding methods to mitigate these risks Explain that connections to the SMTP server can be controlled by granting or denying access to specific

IP addresses, groups of addresses, or by domain name Discuss when encryption should be used, and demonstrate how to enable Transport Layer Security (TLS) encryption Explain the types of authentication that are available for SMTP connections, and discuss the benefits and limitations of each Explain that DNS reverse lookup can be enabled on an SMTP server

to enhance security, but will severely impact performance

Managing the SMTP Service Explain that monitoring the SMTP service will help optimize performance Demonstrate the System Monitor (Performance tool), and discuss which performance counters aid in monitoring and troubleshooting the SMTP service Discuss the importance of logging, and demonstrate the different log file formats Discuss the ways to troubleshoot the SMTP service, and demonstrate the various methods

Customization Information

This section identifies the lab setup requirements for a module and the configuration changes that occur on student computers during the labs This information is provided to assist you in replicating or customizing Microsoft Official Curriculum (MOC) courseware

meet this requirement, perform one of the following actions:

Complete Module 1, “Installing Internet Information Services 5.0” in

Course 2295A, Implementing and Supporting Microsoft Internet Information Services 5.0

Configure the setup requirement manually

Lab Results

After performing the lab in this module, the SMTP service is configured to require authentication No other modules in this course are affected by this change

Overview

Introduction to the SMTP Service

Configuring Support for the SMTP Service

Controlling E-Mail Messages

Configuring Security for the SMTP Service

Managing the SMTP Service

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E-mail is the most widely used Internet service, and the standard protocol that is used by e-mail clients and servers to deliver electronic messages over the Internet is the Simple Mail Transfer Protocol (SMTP)

To provide e-mail message access on your Web servers and applications, Microsoft® Windows® 2000 provides the SMTP service The SMTP service in Microsoft Internet Information Services (IIS) 5.0 enables you to easily

administer your SMTP server, control inbound and outbound e-mail messages, provide security so that the server is not misused or attacked by unauthorized users, and use management tools to optimize the performance of your SMTP server

After completing this module, you will be able to:

Explain what the SMTP service is and how it works

Configure support for the SMTP service

Control e-mail messages for the SMTP service

Configure security for the SMTP service

Manage the SMTP service

In this module, you will learn

about using the Microsoft

SMTP service

Introduction to the SMTP Service

Send

Incoming Message

Remote Message Sent to Remote SMTP Server

Local Message Delivered

SMTP Virtual Server

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With the SMTP service enabled, IIS can send and receive e-mail messages, and this capability enables the following:

Web-based applications to send and receive messages

SMTP servers to exchange e-mail messages

Administrators to receive e-mail messages that are driven by events on the Web server, such as users sending forms from Web pages

Sending and Receiving E-Mail Messages

When a user sends an e-mail message, the delivery process begins with the message being transmitted to an SMTP server If the destination domain name

of the message is local to the SMTP server, the message is stored on that server

If the domain name is not local to the SMTP server, the message is then forwarded to a remote server

To find the remote server, the SMTP server performs a Domain Name System (DNS) lookup for the destination domain The SMTP server checks the DNS Mail Exchanger (MX) record, which is the name of the SMTP server that is servicing all incoming e-mail messages for the remote domain After the Internet Protocol (IP) address is located, the local SMTP server connects to the remote server and sends the message

The SMTP service is not designed as a system for users to retrieve messages by using an e-mail client such as Microsoft Outlook® or Microsoft Outlook Express E-mail message retrieval is defined by the Post Office Protocol (POP), which is not built into the IIS SMTP server The SMTP service is designed to send messages from forms, Microsoft FrontPage®-enabled Webs, or scripts hosted by IIS

To enable users to send e-mail messages to anyone on the Internet directly from

a Microsoft Active Server Page (ASP) script or program on your Web site, Windows 2000 includes a component for handling messages, called the Collaboration Data Objects for Microsoft Windows NT® Server, also known as the CDO for NTS Library

The SMTP service is installed by default when you install Windows 2000 However, if it is uninstalled for any reason, you can reinstall it by performing the following steps:

1 Open Control Panel, and then double click Add/Remove Programs

2 In Add Remove Programs, click Add/Remove Windows Components

3 In the Windows Components Wizard, click Internet Information Services

(IIS), and then click Details

Do not deselect the Internet Information Services (IIS) check box

This will uninstall IIS components

4 In the Subcomponents of Internet Information Services (IIS) dialog box, select the SMTP service check box, and then click OK

Important

Configuring Support for the SMTP Service

Designating an SMTP Virtual Server

Configuring Local and Remote Domains

Examining the SMTP Service Folder Structure

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To effectively support the SMTP service, you need to:

Ensure that each SMTP server is designated as its own virtual server and does not have the same IP address or Transmission Control Protocol (TCP) port number as other virtual servers

Configure local and remote domains for effective e-mail message delivery

Understand the SMTP folder structure that is created during installation

Topic Objective

To explain how to configure

support for the SMTP

service

Lead-in

To effectively support the

SMTP service, you need to

designate the virtual server,

configure the domains, and

understand the SMTP folder

structure

Designating an SMTP Virtual Server

Select the IP Address

Identify the TCP Port Number

SMTP Virtual Server

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When you enable the SMTP service, a default SMTP virtual server is automatically installed A single SMTP server is typically all that is required to send messages from your Web server However, if you require more than one configuration for SMTP, the SMTP service supports multiple virtual servers All SMTP virtual servers require a unique identity, which consists of the IP address and the TCP port number The IP address and TCP port combination must be different for each SMTP virtual server Each SMTP virtual server should also have a unique name

TCP port 25 is the SMTP standard However, more than one virtual server can use TCP port 25, provided that each server is associated with a different IP address

To designate an IP address and TCP port number for an existing virtual server:

1 Click Start, point to Programs, point to Administrative Tools, and then click Internet Services Manager

In Administrative Tools, the IIS console is called Internet Services

Manager; however, when you open the console, it is called Internet Information Services, also known as the IIS snap-in

2 In the IIS snap-in, in the console tree, right-click the virtual server that you

want to configure, and then click Properties

3 On the General tab, in the Name box, type a new virtual server name if you

want to change it from the default

SMTP virtual servers are

identified by the IP address

and the TCP port number

Delivery Tip

Explain that a single SMTP

server is typically all that is

required to send messages

from your Web server, but

that IIS does support

multiple SMTP servers Note

4 In IP address box, select the IP address for this virtual server

The SMTP virtual server can respond to connection requests for all IP addresses configured on the computer

5 To identify the TCP port for each IP address configured for the virtual

server, click Advanced

6 In the Advanced dialog box, either click Add to add a new port number or click a current IP address, click Edit or Remove to change or delete the address and port number, and then click OK

Before you change the configuration on an SMTP virtual server, you should first pause the service To pause the SMTP service for a virtual server,

right-click the virtual server in the IIS snap-in, and then click Pause Pausing

prevents new client connections but enables SMTP service to continue to process existing client connections and to deliver messages

Note

Configuring Local and Remote Domains

Addressed and Delivered

to Local Domain

Remote SMTP Server

Addressed to Remote Domain

Local SMTP Server Forwards Message Using Remote Domain Settings

SMTP Virtual Server

SMTP Virtual Server

IIS Server

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The SMTP server can have two types of domains: local and remote You can

also create an alias domain, which is simply another name for the local domain

There must always be one local default domain on the SMTP server This local default domain is the name of your IIS server and is created automatically when the SMTP service is installed

Local Domains

A local domain is a DNS domain name that is serviced by the local SMTP

server When a message containing a local domain name arrives at the SMTP server, the message is placed as a file in a local folder on the IIS server This folder is created specifically for this purpose when the SMTP service is installed Configuring the local domain is important because any e-mail messages not addressed to the local domain will be routed to other servers for delivery

Alias Domains

An alias domain is another name for the local default domain For example, if

the local domain name is contoso.msft and you want the local server to also receive e-mail messages for nwtraders.msft, you would create an alias for the local domain called nwtraders.msft This would cause the local SMTP server to receive e-mail messages for both contoso.msft and nwtraders.msft Even though there are two names, nwtraders.msft is an alias for the local domain and cannot

be configured separately If you create a new alias domain and decide that you want it to be the new default domain, the previous default domain would become an alias domain

Topic Objective

To explain how to configure

local and remote domains

Lead-in

SMTP virtual servers can

have two types of domains

that you can configure: local

and remote

Delivery Tip

Explain that one local

domain can have multiple

identities by using alias

domains

Remote Domains

Domain names that are not on the local server are known as remote domains

The SMTP service enables you to create and configure a unique delivery requirement for each remote domain For example, you can configure delivery properties for domains that require a secure connection, such as one hosting your corporate Exchange server or a trusted partner’s e-mail server

It is not necessary to configure remote domains for the ordinary delivery of e-mail messages If you don’t specifically configure a new remote domain, the SMTP service will send the message using the settings that you configure in the default virtual server

You cannot rename a domain after you have created it

To create an alias or remote domain:

1 In the IIS snap-in, expand the SMTP virtual server on which you want to

add a remote domain, right-click Domains, point to New, and then click

If you want to make the new alias domain the default local domain,

right-click the alias domain, and then right-click Set as Default

To configure a remote domain, in the details pane of the IIS snap-in, right-click

the domain that you want to configure, click Properties, and then specify the

settings that you want for your remote domain

Note

Delivery Tip

Open the IIS snap-in and

point out the local default

domain Next, demonstrate

how to create an alias and a

remote domain

Examining the SMTP Service Folder Structure

\ Inetpub mailroot Pickup Queue Drop Badmail Route SortTemp Mailbox

Folder

Subfolder Root

Subfolders

SMTP Virtual Server

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When you install the SMTP service, it creates several folders and subfolders on your hard drive The primary mail folder is called Inetpub, which contains the mailroot folder The mailroot folder contains several other folders that are used

by the SMTP service to hold and process messages The default location of the mailroot folder is %SystemRoot%\Inetpub\mailroot These folders and their purposes are described in the following table

These folders Are used to

Pickup Process outgoing messages that are copied to the folder As soon as a properly

formatted text file is copied to the Pickup folder, SMTP collects and delivers it

Queue Hold messages for delivery and sort them by domain so that they can be sent as a group

if they are for remote delivery If a message cannot be delivered, the message is stored

in the Queue folder and then sent again at designated intervals

Drop Receive all incoming messages for all of the domains that are hosted by the SMTP

server

Badmail Store messages that cannot be delivered or returned to the sender

Route, SortTemp, and

Topic Objective

To verify the folder structure

that is created by the SMTP

service

Lead-in

When you enable the SMTP

service, several folders are

created on your hard drive

to organize and process

e-mail messages

Changing Folder Locations

Because the Drop and Badmail folders can accumulate many messages, you may want to change the location of these folders to select the volume on which you store these messages For example, you might want to store incoming e-mail messages on a volume that has sufficient free disk space to handle all incoming messages

To change the default Drop folder:

1 In the IIS snap-in, in the details pane, right-click the default domain, and

then click Properties

2 In the Drop directory box, type or browse to the name of the folder in which you want to drop all incoming messages, and then click OK

The default location is %SystemDrive%\Inetpub\mailroot\Drop Be sure not

to select the Pickup folder as your new Drop folder

To change the default Badmail folder:

1 In the IIS snap-in, right-click the virtual server that you want to configure,

and then click Properties

2 On the Messages tab, in the Badmail directory box, type or browse to the

directory that you want to use to store undeliverable messages, and then

click OK

The default location is %SystemDrive%\Inetpub\mailroot\Badmail You can designate a different folder, provided that it is on the same computer as the SMTP service

Using the SMTP Folder Structure to Test the SMTP Server

You can also use the SMTP folder structure to test your SMTP server by

composing a message text file and then copying it into the Pickup folder When

you compose the text file, you must include envelope header information The following is an example of a text file with envelope header information:

x-sender: jonmorris@nwtraders.msftx-receiver: jeffsmith@contoso.msftFrom: jonmorris@nwtraders.msftTo: jeffsmith@contoso.msftSubject: Hello from JonAnything after the blank line after the subject heading

is the body of the message

In the example above, the sender header identifies the sender, and the receiver header identifies a single recipient If you want to include multiple recipients, add an x-receiver header for each recipient The headers must appear first in the text file, with the x-sender header listed first A blank line (carriage return and line feed) must precede the message The text file must be in ASCII format, not Unicode

x-Some settings are applied only to messages that are received by the

SMTP service For example, when a message is dropped into the Pickup folder,

message size limits are not applied if the message is delivered locally

Note

Controlling E-Mail Messages

Setting E-Mail Message Limits

Limiting Connections

Configuring Delivery Options

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Several settings control the flow of messages to and from your SMTP server The default settings will be sufficient in most cases but, as an administrator, you can adjust these settings to meet your specific business needs On a busy server, for example, adjusting e-mail message limits, limiting connections, and setting delivery options can help you improve the performance of your server

Topic Objective

To explain how to control

e-mail messages in the

SMTP service

Lead-in

There are several ways that

you can control incoming

and outgoing e-mail

messages on your SMTP

virtual server

Setting E-Mail Message Limits

Limiting Message Size

Limiting Session Size 10,240 KB

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To improve the performance of your SMTP server, you can adjust various message, session, and recipient settings for incoming and outgoing e-mail messages By setting limitations on your SMTP server, you prevent the server from accepting unacceptably large amounts of data through e-mail, and you control the numbers of outgoing messages and connections You can set limits

on the amount of data that the server will accept and send by configuring message size, session size, number of messages per connection, and number of recipients per message

Limiting Message Size

Message size controls the maximum size of a message (including any attachments) that the SMTP service will accept The default message size is 2,048 kilobytes (KB); the minimum is 1 KB

Limiting Session Size

Session size controls the maximum amount of data that the server will accept during a session Multiple messages may be transferred between servers during

a single session However, if the total size of the messages exceeds the maximum session size, the SMTP service will disconnect This setting is important because, when you set a low limit, it can deter the use of your SMTP server for unauthorized delivery of bulk e-mail messages The default session size is 10,240 KB

Although decreasing the value of this setting will limit the length of connections, it will also cause remote servers to make additional connections to continue sending messages after being disconnected If the session size limit is too small, then your server will spend more time creating many short sessions than it would have spent creating fewer longer ones Also, to ensure that your large messages can be sent, the session size limit should be greater than or equal to the message size limit

Topic Objective

To explain how to set e-mail

message limits

Lead-in

To improve the performance

of your SMTP server, you

can adjust various message,

session, and recipient

settings for incoming and

outgoing e-mail messages

Limiting the Number of Messages per Connection

You can also limit the number of messages that are sent in a single connection, and allow multiple connections to deliver messages to a remote domain After the limit is reached, a new connection is automatically opened and the transmission continues until all messages are delivered

For example, when you send many messages to a remote domain, you can limit the number of messages per connection to a relatively low number, such as 25

As a result, when you send 75 messages in one session, SMTP sends the first 25 messages As those are being sent, the server opens a new connection, and sends another 25, and as those are being sent, it sends 25 more, and so on Therefore, there would be three simultaneous connections that are delivering messages to one destination The default number of messages per connection is 20; the maximum is two billion

Limiting the Number of Recipients per Message

When a single message needs to be delivered to thousands of e-mail addresses,

a common technique is to use the CC or BCC fields However, large numbers

of recipients per message over a single connection might burden your SMTP server By limiting the number of recipients per message, you allow your server

to service other incoming requests

The default setting of 100 recipients is specified in RFC 821, and is the SMTP standard When the maximum number of recipients is exceeded, the SMTP service opens a new connection to process the number of recipients that are over the limit For example, if the message is sent to 103 people, the server will process 100 messages in one connection, and then open a new connection to process the three remaining messages

To set e-mail message limits:

1 In the IIS snap-in, right-click the virtual server that you want to configure,

and then click Properties

2 On the Messages tab, select the appropriate check boxes, enter the limits that you want to enforce on your virtual sever, and then click OK

Delivery Tip

Display the Messages tab

on property sheet of the

default SMTP virtual server

and point out how to set

e-mail message limits

Limiting Connections

Limit the Number of Incoming and Outgoing Connections with Other SMTP Servers

SMTP Virtual Server

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Whenever a message is sent to or received from a remote server, a connection is initiated To improve the performance of your SMTP server, you can limit the number of connections that you allow to and from the server The degree of improvement that is achieved depends on the speed and capacity of your server hardware and network connections

To configure incoming and outgoing connections:

1 In the IIS snap-in, right-click the virtual server that you want to configure,

and then click Properties

2 On the General tab, click Connection

3 Under Incoming or Outgoing, select the Limit connections to check box and, in the Limit connections to box, type the number of concurrent

connections that you want to allow

For incoming and outgoing connections, the default value is 1000 and the minimum is one

4 In the Time out (minutes) box, type the time allowed before an inactive

connection is closed

5 To limit the number of connections to any single remote domain, select the

Limit connections per domain to check box and, in the corresponding box,

type the number of connections per domain that you want to allow, and then

click OK

The default is 100 connections This number should be less than or equal to

the value for the Limit connections to box

6 In the TCP port box, specify the TCP port that you want to use for

You can limit the number of

incoming and outgoing

connections to your server

to improve its performance

Delivery Tip

Demonstrate how to

configure the incoming and

outgoing messages

Configuring Delivery Options

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To determine how your messages are sent to other SMTP servers, the SMTP service enables you to set retry intervals, configure a smart host and

masquerade domain name, and set a maximum hop count

Setting Retry Intervals

Retry attempts and retry intervals determine how many times the SMTP service will resend a message and at what intervals before the message is considered undeliverable The default settings allow the SMTP service to attempt delivery

of a message for two days before returning a non-delivery report (NDR)

If a message cannot be delivered on the first attempt, the SMTP service resends

it from the Queue folder after a specified time You can set the interval between delivery attempts and also designate the number of times that the server will attempt to deliver a message After the limit is reached, the message is returned

to the sender with an NDR The NDR is placed in the Queue folder and goes through the same delivery process as messages If the NDR reaches the maximum number of retry attempts, both the NDR and message are sent to the Badmail folder

To configure retry intervals:

1 In the IIS snap-in, right-click the virtual server that you want to configure,

and then click Properties

2 On the Delivery tab, enter the limits that you want to enforce on your SMTP virtual server, and then click OK

Topic Objective

To explain how to configure

delivery options

Lead-in

Setting delivery options can

include configuring a smart

host, setting retry intervals,

designating a masquerade

domain name, and setting

the hop count

Configuring a Smart Host

A smart host acts as a gateway for e-mail messages between networks The smart host setting can be useful if your IIS SMTP servers are not all directly connected to the Internet For example, you can connect one SMTP server to the Internet and configure all the others to use it as a smart host You can also specify a smart host when you want all non-local messages to be processed by a single server, which is often a dedicated and well-connected mail server such as Microsoft Exchange 2000 Therefore, the local SMTP server is relieved of the task of delivering messages

For some situations, it makes sense to route most outgoing messages through a smart host However, you might have a specific domain whose server can be accessed through a more efficient route To use that route, you would create a new remote domain and then configure a smart host for that remote domain The domain setting overrides the SMTP virtual server setting The default is to send all remote messages to the smart host, not to attempt direct delivery

You can identify the smart host by domain name or by IP address If you use an IP address, enclose it in brackets [ ] to increase system performance Because the brackets identify the value as an IP address, DNS lookup is bypassed

Designating a Masquerade Domain Name

A masquerade domain name is a name that you want to appear in message headers The masquerade domain name replaces the actual local domain name that appears in the Mail From lines in the protocol

If you have an SMTP server that is configured as a smart host, you may want to use the masquerade domain name setting on the smart host to ensure that all outgoing messages are sent from a single domain For example, if your organization’s messages are sent from the domains mail1.contoso.msft and mail2.contoso.msft, you can use the masquerade domain name on the smart host to show that all of the messages are from contoso.msft

Tip

Setting the Maximum Hop Count

You can limit how many servers a message is allowed to pass through before the message either reaches its final destination or is determined to be

undeliverable This setting is called the hop count After you set the hop count,

the SMTP server counts the hops that are listed in the Received lines of the message header When the number of Received fields exceeds the maximum hop count setting, the message is returned to the sender with an NDR The default is 15 hops

To configure a smart host, masquerade domain name, and maximum hop count:

1 In the IIS snap-in, right-click the virtual server that you want to configure,

and then click Properties

2 On the Delivery tab, click Advanced

3 In the Advanced Delivery dialog box, enter the limits that you want to enforce on your SMTP virtual server, and then click OK

To allow for network delays, you can set a delay period to expire before sending the delivery notification The minimum value is one minute, the default value is 12 hours, and the maximum value is 9,999 days

You can also set an expiration timeout for messages that have not been delivered after all retries The minimum value is one minute, the default value is two days, and the maximum value is 9,999 days Reducing this setting will allow you to be notified more quickly when there are delivery problems

Configuring Security for the SMTP Service

Configuring Connection Control

Enabling Encryption

Enabling Authentication

Controlling Relay Access

Verifying Connections Using DNS Reverse Lookup

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SMTP servers are not usually domain controllers and do not normally contain sensitive application data However, you should still ensure that your SMTP servers have the appropriate security settings and are protected from

unauthorized users and attacks, such as denial-of-service attacks Denial of service occurs when the SMTP server becomes so overloaded with unwanted messages that it cannot process legitimate messages

To help prevent attacks on your server, you can configure the SMTP service to allow or deny connections to other servers based on their IP addresses and domain names You can use encryption to protect data and also require that users authenticate to the SMTP server before they can send e-mail messages Additionally, you can control relay access, and configure the SMTP server to perform a DNS reverse lookup on incoming messages to confirm that they originate from a legitimate domain

Topic Objective

To explain how security

works on SMTP servers

Lead-in

It is important to have the

appropriate security settings

on your SMTP servers

Configuring Connection Control

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By default, the SMTP virtual server is accessible to all IP addresses However, you can control connections to your SMTP virtual servers by granting or denying access to a specific IP address, a group of addresses, or a domain name This ability can be useful on an intranet when you want to limit what computers can connect to the SMTP server

To grant or deny specific connections:

1 In the IIS snap-in, right-click the virtual server that you want to configure,

and then click Properties

2 On the Access tab, click Connection

3 Click Add to add a single computer, a group of computers, or a domain

name to the list of computers that you want to grant or restrict

4 To delete a computer from the list, select it from the Computers list, and then click Remove