
Special Edition Microsoft Exchange Server 5.5


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Setting Up the Site Connector and Dynamic RAS Connector
This chapter is the first in this book dedicated to the specifics of linking two
or more Microsoft Exchange sites. By now, you should have learned enough to be able
to select the most appropriate connector between the Exchange servers in your organization.
This chapter deals with the two connectors designed to link only Microsoft Exchange
severs. Other connectors, such as X.400 or Internet Mail Connector, can be used to
link Exchange servers and to provide a gateway to foreign mail systems. The two connectors
used only between Exchange servers are:
- Site Connector--Full-time message link over high-bandwidth network links
- Dynamic RAS Connector--Part-time scheduled message transfer over low-bandwidth
lines
This chapter covers the basics of setting up a Site Connector and a Dynamic RAS
Connector. Because a site can have any combination of connectors to a remote site,
or even multiple connectors of a certain type, you will need to repeat the same steps
outlined in this chapter each time you set up a new connector.
Understanding Site Connectors
The Microsoft Exchange Site Connector provides the most direct link between sites.
Communication is handled through Remote Procedure Calls between servers in each site.
Messages do not need to be converted to a different format (such as X.400) to be
transmitted to a different site.
You should be familiar with the following concepts before you attempt to set up
and configure a Microsoft Exchange site connector:
- Target servers--The list of Exchange servers in the remote site that will
be involved in transferring messages to and from the local site.
- Routing costs--A number assigned to each connection on a relative scale
from 1 to 100. Messages are first routed to connections that have the lowest cost;
message transfer is distributed evenly across all connections that have the same
assigned cost. You can set routing costs for a site as a whole as well as for individual
Exchange servers.
- Bridgehead server--A specific Microsoft Exchange server in a site designated
to establish communication with the remote site. Normally, the specific server that
establishes this connection varies, depending on messaging traffic. Designating a
bridgehead server is useful for controlling the message-transfer points between two
sites.
Installing a New Site Connector
Installing a site connector to exchange messages between sites is a two-step process.
First, you must set up a connector in the local site. The connector enables message
traffic to the target site. Second, to receive messages from the remote site, you
must install a corresponding site connector in the remote site. When you set up a
new connection between sites, the Exchange Administrator program automatically prompts
you to create the second site connector in the remote site. If you do not create
a remote site connector (or cannot, due to access restriction in that site), you
must coordinate your efforts with the remote site administrator to negotiate a successful
connection between sites. The remote administrator must create a corresponding connector
that links to your site.
Before you install a new site connector, make certain that the following conditions
are met:
- The underlying network between two sites is properly configured and operational.
- All Microsoft Exchange services are running on both sites.
- You know the exact server at the remote site to which you want to connect.
- If you want to establish the corresponding site connector at the remote site,
be sure that you have administrative access rights to the foreign Exchange server
and domain if the Exchange server resides in a different domain.
To create a new Site Connector, follow these steps:
- 1. Navigate through the Exchange administrator program's hierarchy, and
highlight the Connections object (see Figure 17.1). The right display window shows
all the connections currently running within this site.
FIG. 17.1 The Exchange
Administrator program's display window shows all current site connections.
-
- 2. Pull down the File menu and choose New Other; then choose Site Connector
from the New Other menu. The New Site Connector dialog box appears (see Figure 17.2).
- 3. In the text box, type the name of a specific Microsoft Exchange server
at the remote site.
NOTE: The server name that you enter is used to identify the remote
site and does not necessarily mean that this server is the machine that will handle
message traffic between sites. Conceptually, a Site Connector resides at the site,
not on any particular Exchange server.
FIG. 17.2 Enter the name
of an Exchange server at the remote site.
- 4. Click OK. The Administrator program attempts to locate and access that
server on the network.
NOTE: You must have a name resolution mechanism, such as WINS, DNS,
HOSTS file, LMHOSTS file, or a configured browser service, to resolve the name of
your Exchange server. If a name resolution mechanism is not functional, you will
not be able to set up either the local or the corresponding site connector.
If you attempt to create a site connector to a site where such a connector already
exists, you will be notified of the situation and will not be allowed to create another
connector.
When creating a site connector to a server in another Windows NT domain, you need
to make sure the account in which you are creating the connector not only has administrative
rights to the second domain, but also administrative rights on the Exchange server
in this second site. These rights are required to create the connector.
Configuring Site Connector Properties
After creating a new Site Connector, you will need to configure its properties.
The property pages for the Exchange Site Connector are as follows:
- General--Enables you to set an overall routing cost for this connector
and designate a bridgehead server, if appropriate.
- Target Servers--Enables you to select the specific servers in the remote
site that will receive messages from the local site.
- Address Space--Allows you to assign various email address types and associated
routing costs for this site connector object.
- Override--Enables you to specify custom log in information if a target
server is outside the local Windows NT domain.
The General Page The General page is where you set Site Connector
communication options. Primarily, you will define which site you are connecting to
and which servers specifically will handle that connection. The following steps guide
you through configuring the General page.
- 1. Click the General tab of the Site Connector property pages (see Figure
17.3).
- 2. If you want, type a new name for this site connector in the Display
Name box. The default display name is in the format Site Connector (site name).
- 3. If you want, type a different directory name for this site connector
in the Directory Name box. The default directory name is in the format Site
Connector (site name).
FIG. 17.3 Use the General
Site Connector property page primarily to define the site to which you are linking.
- 4. The Target Site box shows the name of the remote site to which
you are connecting. This data is provided for your information only. To change the
target site at this point, you must click Cancel to exit from the property pages
and create a new site connector.
- 5. In the Cost box, enter a routing Cost for the site connector.
An Exchange server uses this cost to determine whether to use this connection over
other available connections. By default, a new site connector has a routing cost
of 1.
- 6. If you want, specify a bridgehead server that will handle communication
with the remote site. By default, the Any Server option is selected, and communication
will be handled by the combination of target servers specified in the remote site's
connector. If you select a specific server, that one machine will process all message
transfer through the site connector.
- 7. If you want, make an entry in the Administrative Note box.
- 8. Click Apply to set these properties and continue setting other
properties.
- 9. When you finish making settings, click OK to return to the Administrator
program.
The Target Servers Page Use the Target Servers page to set which
remote Exchange servers will receive messages through this Site Connector. Servers
that do not get listed are excluded from communication with the local site.
- 1. Click the Target Servers tab of the Site Connector property pages (see
Figure 17.4).
- The Site Servers list on the left side of the dialog box shows all the
available servers at the remote site. The Target Servers list on the right
side of the dialog box shows the Exchange servers at the remote site that communicate
to the local site through this site connector.
- 2. Select a server from the Site Servers list and then click Add
to make it a target server for this site connector.
- To remove a server from the Target Servers list, select it and then click
Remove.
- 3. The Target Server Cost section displays the routing costs for
the selected target server. In the text box, type the desired routing cost for each
server and then click Set Value to store that value.
FIG. 17.4 Select the servers
in the remote site to link through this Site Connector.
- 4. Click Apply to set these properties and continue setting other
properties.
- 5. When you finish making settings, click OK to return to the Administrator
program.
The Address Space Page The Address Space page is where you tell
Exchange which messages are routed through this Site Connector. Without an appropriate
entry, messages will not find their way to the remote site.
- 1. Click the Address Space tab of the Site Connector property pages (see
Figure 17.5).
- 2. Click one of the New address types (General, X.400, MS Mail, Internet)
to add an address space entry for this connector. Select an existing address space
entry and click Edit to modify it or click Remove to delete it.
- 3. Click Apply to set these properties and continue setting other
properties.
- 4. When you finish making settings, click OK to return to the Administrator
program.
The Override Page If the site to which you want to connect is
not within the same Windows NT domain (or within a trusted domain), you must specify
logon information for this site connector. This property page allows you to enter
such data. Use the following steps:
- 1. Click the Override tab of the Site Connector property pages (see Figure
17.6).
FIG. 17.5 Add or modify
address-space entries to define message routing for this connector.
FIG. 17.6 Configure connector
logon information to a remote Windows NT domain.
-
- 2. In the Windows NT Username box, type the name of the account
that you want to use to log on.
- 3. In the Password box, type the password that is associated with
that account.
- 4. In the Confirm Password box, type the password again.
- 5. In the Windows NT Domain Name box, type the domain in which
the remote site resides.
- 6. Click Apply to set these properties and continue setting other
properties.
- 7. When you finish making settings, click OK to return to the administrator
program.
If a Site Connector is not set up in the remote site, the dialog box shown in
Figure 17.7 appears. It prompts you to create one.
Click No if you do not want to create and configure the remote site connector
at this time. If you do click No, realize that message transfer will not occur until
you set up that remote Site Connector at some later time. Click Yes to create and
configure a site connector for the remote site at this time. The property page for
the second site connector appears (see Figure 17.8).
FIG. 17.7 Specify whether
to create a corresponding site connector at the remote site.
FIG. 17.8 General property
page for the corresponding site connector at the remote site.
Configure this site connector following the procedure that you use to configure
a local site connector. Keep in mind that the target servers now are Microsoft Exchange
Servers that were the local servers in the previous connector configuration.
After you create and configure a site connector between two sites, the remote
site appears in your Exchange Administrator program's hierarchy view. You can view
all the Exchange objects at the remote site, but you cannot make any changes unless
you log on directly to an Exchange server at that site. To share address lists with
the connected site, for example, you must set up a directory replication connector
to that site. See Chapter 18 for setting up directory replication between sites.
Deleting a Site Connector
If you want to remove a site connector that services message traffic between two
sites, you first must determine what other services depend on the existence of that
site connector. If other connections (such as a directory replication connector)
rely on the site connector as the only link for message transport, you cannot delete
that site connector; you first must delete any other dependent connections and then
delete the site connector. If you do not want to delete the other connections, you
must supply another link between sites that can service the other connections.
To delete a site connector, follow these steps:
- 1. Navigate through the Administrator Program's site display, and click
the Connections object.
- 2. Select the Site Connector that you want to delete.
- 3. Pull down the Edit menu and choose Delete, or press the Delete key
on the keyboard.
NOTE: To disable all message transfers between sites, you must remove
connectors from both the local and the remote sites. Log on to the remote Exchange
server and then remove the site connectors, using the process described in this section.
Using the Dynamic Remote Access (RAS) Connector
The Microsoft Exchange Dynamic RAS Connector uses existing Windows NT Remote Access
Services to facilitate temporary, low-bandwidth messaging links. The Dynamic RAS
Connector establishes a temporary scheduled link to a remote Exchange server via
a modem or any other RAS-compatible transport (for example, ISDN or X.25), transfers
messaging data, and then disconnects. This section covers installing and configuring
the Dynamic RAS Connector to link your messaging sites.
Before installing a Dynamic RAS Connector, you must do the following:
- 1. Install the Windows NT Remote Access service on the Exchange server
that will be establishing the connection.
- 2. Configure the hardware required for the remote access link (for example,
a modem or ISDN terminal adapter).
- 3. Enter a RAS phone-book entry for the remote Exchange server. Use your
Windows NT documentation or online help to guide you through this process.
- 4. Know the name of the remote server with which you want to establish
the link.
Installing a Dynamic RAS Connector involves these steps:
- Install the RAS MTA transport stack. Because the MTA will use a transport that
is not supported directly through Microsoft Exchange server, you must define an external
(Windows NT Remote Access Service) transport stack to use in message transfer.
- Install and configure the Dynamic RAS Connector itself. Follow the steps in the
following sections.
Installing the RAS MTA Transport Stack
You add the RAS MTA Transport Stack from within the Administrator program. Follow
these steps:
- 1. From the Administrator program, select New Other from the File menu,
then select MTA Transport Stack from the submenu. The New MTA Transport Stack dialog
box appears (see Figure 17.9).
- The Type section of the dialog box lists the available MTA transport stacks
on this Exchange server.
NOTE: Only the RAS MTA Transport Stack is used for the Dynamic RAS
Connector.
- The Server section of the dialog box lists all the servers at the current
site.
FIG. 17.9 The New MTA
Transport Stack window is used by the Dynamic RAS Connector (and the X.400 connector)
to select an underlying transport for message transfer.
- 2. Select RAS MTA Transport Stack from the list of available transports.
- 3. Select the server in your local site that will handle the remote-access
connection. The transport stack will be installed on that server.
- 4. Click OK to accept the transport stack and Exchange server settings.
The General page of a new Dynamic RAS Connector appears (see Figure 17.10).
- The MTA Transport Stack has only two property pages to configure: General and
Connectors. Configuration usually is a one-time process unless you change the local
MTA callback number. Refer to the Connector property page to view the Dynamic RAS
Connectors that use this MTA Transport Stack.
FIG. 17.10 The RAS MTA
Transport Stack property pages.
Configuring MTA Transport Stack Property Pages
Settings in the MTA Transport Stack pages affect all Dynamic RAS Connectors that
use it. The following section guides you through configuring the RAS Transport Stack.
The process is similar to configuring MTA Transport Stack for X.25, TCP/IP, or TP4
connections as well.
The General Page The General page lets you configure a display
name and callback number for this RAS MTA Transport Stack. Complete the following
steps to alter the General page properties:
- 1. In the Name box, type the name under which you want this transport
stack to appear in the Exchange Administrator object display window. You cannot modify
this name after you create it. By default, the stack is named in the RAS format (server
name).
- 2. In the MTA Callback Number box, enter the phone (or other device)
number of the local Microsoft Exchange server.
NOTE: The Windows NT Remote Access service uses a callback number
as a means of authentication. The remote server receives a call, gets the callback
number, hangs up, and dials the originator to establish a RAS link. It may be necessary
to insert a prefix of an outside line number before the call back number when dialing
out from a business phone at a company.
- 3. Click Apply to set these properties and continue setting other
properties.
- 4. When you finish making settings, click OK to return to the Administrator
program.
The Connectors Page The connectors page of the RAS Transport
Stack Properties allow you to view and edit each connector that uses this Transport
Stack.
- 1. Click the Connectors tab of the RAS MTA Transport Stack dialog box
(see Figure 17.11).
- The Connectors page lists all the Dynamic RAS Connectors that use this transport
stack. If you have set up the RAS MTA Transport Stack for the first time, the list
is blank. After you set up at least one Dynamic RAS Connector, that connector is
displayed in this page; you can select it and then click Edit to modify its
properties.
- 2. Click Apply to set these properties and continue setting other
properties.
- 3. When you finish making settings, click OK to return to the Administrator
program.
FIG. 17.11 The RAS MTA
Transport Stack Connections page lists all current Dynamic RAS Connectors.
After setting up the Transport Stack you are ready to create a RAS Connector.
Keep in mind that the Transport Stack is the communication layer for the RAS Connector,
and is essential in its operation.
Creating a New Dynamic RAS Connector
You create a new Dynamic RAS Connector from the Microsoft Exchange Administrator
program. If you have not yet installed the RAS MTA Transport Stack, you must do so
before proceeding.
Installing a New Dynamic RAS Connector
Use the following steps to install a new Dynamic RAS Connector:
- 1. Drop down the Exchange Administrator File menu and choose New Other.
- 2. Choose Dynamic RAS Connector from the submenu. The pages for the new
connector appear.
Configuring a New Dynamic RAS Connector
The following are the pages that you use to configure a Dynamic RAS Connector:
- General--Enables you to specify the name, remote server, MTA transport
stack, maximum message size, and Windows NT RAS phonebook entry.
- Schedule--Enables you to set a connection schedule for this Dynamic RAS
Connector.
- RAS Override--Enters alternative logon and RAS callback number information.
- MTA Override--Enables you to change the default MTA settings when you
use this Dynamic RAS Connector.
- Connected Sites--Enables you to view, add, or modify addressing of the
connected sites.
- Address Space--Enables you to define which messages pass through this
connector.
- Delivery Restrictions--Enables you to specify which users can (and cannot)
send messages to this Dynamic RAS Connector.
The General Page The General page lets you set the communication
methods for this Dynamic RAS Connector. Part of this configuration will be to enter
the telephone number data for the remote site, so have that information available
when configuring the following options:
- 1. Click the General tab of the Dynamic RAS Connector property pages (see
Figure 17.12).
FIG. 17.12 Set general
Dynamic RAS properties.
- 2. In the Display Name box, type the name that you want to appear
in the Microsoft Exchange Administrator display window.
- 3. When you create a Dynamic RAS Connector, enter a name for it in the
Directory Name box.
- 4. In the Remote Server Name box, type the name of the Microsoft
Exchange server to which you are establishing a link.
- 5. From the MTA Transport Stack drop-down list, select the local
Exchange server that will handle the remote access connection.
- 6. From the Dial Up Networking entry, select the entry that dials into
the remote server.
- If you have not yet created an appropriate entry, complete the following:
- Click Start at the bottom of your screen.
- Open accessories and drag to Dial Up Networking (DUN).
- Once you have highlighted the option of DUN, click the local Exchange server's
Dial Up Network entries. In the example connector (see Figure 17.13), this brings
up the Windows NT RAS entry in the Dial Up Network for GARLAND LAW.
FIG. 17.13 The Windows
NT remote access service Dial Up Network shows an entry set to dial into a remote
Exchange server.
-
- You can also create a phonebook entry by clicking the RAS Phone Book button,
and selecting New from the Dial Up Networking window that appears.
TIP: Setting an upper limit for message sizes often is a good idea.
Particularly with a low-bandwidth link (for example, a 28.8-Kbps modem), several
large messages that have attachments could easily create a bottleneck through this
connector.
- 7. If you want to set an upper limit for the size of messages that pass
through this connector, click the Maximum (K) radio button, and in the text
box, type the size limit (in kilobytes). A message that exceeds this maximum size
will be returned as undeliverable. By default, the No Limit option is selected,
and messages of any size can pass through the connector.
- 8. Make an entry in the Administrative Note box, if you want.
- 9. Click Apply to set these properties and continue setting with other
properties.
- 10. When you finish making settings, click OK to return to the Administrator
program.
The Schedule Page Use the Schedule page to control how often
the Dynamic RAS Connector becomes active and initiates a connection. Follow these
steps:
- 1. Click the Schedule tab of the Dynamic RAS Connector property pages
(see Figure 17.14).
FIG. 17.14 Set connection
times for this Dynamic RAS Connector.
- 2. Click one of the four options that determine when this Dynamic RAS
Connector connects:
- Remote Initiated--This option sends messages only when the remote MTA
connects to this MTA. Both MTAs must have the two-way alternative option selected.
CAUTION: Only one MTA can be configured to be remote-initiated.
Otherwise, if both MTAs are waiting for the other to initiate the connection, the
messages will never be delivered.
- Never--This option effectively disables this Dynamic RAS Connector.
- Always--This option provides a remote access connection whenever messages
need to be transferred. By default, this option is selected.
- Selected Times--This option enables the Dynamic RAS Connector to initiate
communication, based on the time grid.
- 3. If you chose Selected Times in step 2, the Detail View option
buttons become available. Choose either 1 Hour or 15 Minute; the time
grid changes its scale accordingly.
- 4. If you chose Selected Times in step 2, choose the time blocks
that you want to use for the connection. In Figure 17.14, the Dynamic RAS Connector
is set to initiate connections at 6 a.m. and 6 p.m. on weekdays, and at noon on weekends.
- 5. Click Apply to set these properties and continue setting other
properties.
- 6. When you finish making settings, click OK to return to the Administrator
program.
The RAS Override Page The RAS Override page is designed to supersede
RAS settings for both logon information and callback numbers. The following steps
guide you through these settings.
- 1. Click the RAS Override tab of the Dynamic RAS Connector property pages
(see Figure 17.15).
FIG. 17.15 RAS Override
allows you to configure custom logon information from this page.
- 2. In the Windows NT Username box, type the name that you want
to use to authenticate this Dynamic RAS Connector.
- 3. In the Password box, type the password.
- 4. In the Confirm Password box, type the password again.
- 5. In the Windows NT Domain Name box, type the name of the domain
where the remote server resides.
- 6. In the Optional Phone Numbers section, type a phone number in the MTA
Callback Number box.
- 7. Enter a different phone number in the Overriding Phone Number
box.
- 8. Click Apply to set these properties and continue setting other
properties.
- 9. When you finish making settings, click OK to return to the Administrator
program.
The MTA Override Page Because of the typically low-bandwidth
links associated with a remote access connection, it often is a good idea to set
a different MTA configuration specifically for messages transmitted through this
Dynamic RAS Connector. You set the MTA default configuration through the Site MTA
property pages. Any setting in the MTA Override property page supersedes default
MTA settings when the Dynamic RAS Connector negotiates a connection (see Figure 17.16).
FIG. 17.16 Set specific
override properties for the Message Transfer Agent.
The Connected Sites Page This property page lets you view which
sites are linked via the current RAS Connector. Figure 17.17 shows a Connected Sites
property page listing linked sites (blank if none).
Sites listed in the Connected Sites page can receive messages from the local site
via the current connector. If a site is not listed it may be available to view other
links established via other connectors.
The Address Space Page The Address Space page (see Figure 17.18)
defines which recipients can be reached through this connector. Only enough addressing
data is provided to distinguish messages that should be sent through this connector.
Routing costs are entered along with each Address Space entry.
The Delivery Restrictions Page The Delivery Restrictions page
specifies which users can and cannot send messages through this connector.
- Accept Messages From. Creates an exclusive list of recipients who have permission
to send messages through this Dynamic RAS Connector.
- Reject Messages From. Lists specific recipients who are denied permission to
send messages through this Dynamic RAS connector.
FIG. 17.17 View directly
and indirectly connected Exchange sites.
FIG. 17.18 Identify routes
to this connector by using Address Space entries.
To set delivery restrictions, follow these steps:
- 1. Click the Delivery Restrictions tab of the Dynamic RAS Connector property
pages (see Figure 17.19).
- 2. In the Accept Messages From or Reject Messages From section, click
the List option button.
- 3. Click the Modify button below each list to display the Microsoft Exchange
address list.
FIG. 17.19 Delivery restrictions
allow you to specify who can access the Dynamic RAS Connector.
- 4. Select the desired senders to include or exclude as per the above lists
and then click OK.
- 5. Click Apply to set these properties and continue setting other
properties.
- 6. When you finish making settings, click OK to return to the Administrator
program.

