Gateway Passthrough Support

Microsoft Exchange Server users can send and receive mail through gateways installed on Microsoft Mail (PC) postoffices. The Connector postoffice needs to have the access component or gateway installed, and the Microsoft Exchange Server site needs address space mapped. Custom recipients for Microsoft Mail (PC) mailboxes might need to have their default e-mail or proxy address updated so that mail sent to the old address can be resolved to match the custom recipient.

Migrating to the Internet Mail Service

For your users to send to and receive mail from the Internet, you need to replace the MS Mail (PC) SMTP connector with the Internet Mail Service. The following requirements must be met before you make the switch:

• Mail addressed with the global address list and sent between Microsoft Mail (PC) and Microsoft Exchange Server is routed and delivered without any problems. The easiest way to do this is to connect the two systems with the Microsoft Mail Connector, but any type of connection can be used.
• All Microsoft Mail mailboxes that will send or receive mail through the Internet Mail Service with their current address must be in the Microsoft Exchange Server global address list as custom recipients. The easiest way to do this is to configure directory synchronization and wait for the custom recipients to be created. You can skip this step, but the SMTP addresses of MS Mail (PC) users default to: IMCEAMS_<network>_<postoffice>_<mailbox> @<site>.<organization>.<domain>
• All Microsoft Mail postoffices have an access component for the SMTP gateway.
• The Internet Mail Service is configured and tested on a server in any site in the organization. Mail sent from Microsoft Exchange Server mailboxes is delivered to the Internet or SMTP system.

After these conditions have been met in this order, make adjustments to addressing and routing on Microsoft Exchange Server and on the Domain Name System (DNS) MX record for the site's domain before the gateway can be shut down and the use of the gateway is migrated. This process depends on your configuration.

Migrating from the Microsoft Mail (PC) SMTP Gateway to the Internet Mail Service

How you migrate to using the Internet Mail Service depends on how you were using the SMTP gateway and how you plan to use the Internet Mail Service. The following table summarizes the three approaches.

SMTP gateway uses	Internet Mail Service uses
Primary connection to the Internet.	Primary connection to the Internet.
Another system connects to the Internet, and the SMTP gateway handles mail for MS Mail users only.	Another system connects to the Internet, and the Internet Mail Service handles mail for MS Mail and Microsoft Exchange Server users only.
Another system connects to the Internet, and the SMTP gateway handles mail for MS Mail users only.	Internet Mail Service connects to the Internet and handles routing for all e-mail systems in your organization.

Microsoft Exchange Server supports multiple Internet e-mail addresses for recipients. For example, inbound messages can use any address defined for a user (but all outbound messages must use a primary address). This allows you to maintain your existing addresses if you want to change address conventions.

Addressing configured for an SMTP gateway	Addressing configured for the Internet Mail Service	Method
Uses default structure: user@postoffice.network.domain	Use default for site:user@domain	Switch address conventions
Uses default structure: user@postoffice.network.domain	Preserve addresses for migrated users	Maintain internal addressing conventions
Uses alias table to hide default structure from outside world	Preserve outside world addresses	Maintain external addressing conventions
Uses default structure: user@postoffice.network.domain	Use default for site:user@domain but support old addresses	Use multiple e-mail addresses

Switching Address Conventions

Migrating to Microsoft Exchange Server can give you a chance to start over with standardized addresses. When new mailboxes are created, an SMTP address is generated based on the rules in the Site Addressing property page. This address can be replaced or supplemented with other e-mail addresses. Set up this before beginning to migrate mailboxes.

This is the easiest way to reduce directory synchronization chores during migration. However, there are some additional steps you need to take for this approach to succeed:

• Install and test the Internet Mail Service.
Establish a new MX record for the new address. Mail sent to the new addresses will be routed to the Internet Mail Service, while mail sent to the old addresses is routed to the SMTP gateway.
• Inform users of their new SMTP addresses after their mailboxes are migrated.
As users migrate from Microsoft Mail to Microsoft Exchange Server, their SMTP address changes. The users must let their correspondents know of the changes to their address. You can use directory export to create the list of addresses.
• Retain the Microsoft Mail address as the primary or secondary Microsoft Mail type e-mail address of the Microsoft Exchange Server mailbox when migrating entire postoffices.
If users retain their Microsoft Mail address, and mail sent to their postoffice is routed to the Microsoft Mail Connector, mail arriving at the SMTP gateway addressed to the old address is routed to them.
• After migrating all mailboxes to Microsoft Exchange Server mailboxes, continue operation of the SMTP gateway until the flow of mail is reduced significantly.
Inform those users still receiving mail from the SMTP gateway that mail addressed to the old SMTP address used by the SMTP gateway will not be delivered. Shut down the gateway.

Maintaining Internal Addressing Conventions

By default, the SMTP gateway creates addresses for all Microsoft Mail mailboxes based on their network, postoffice, and mailbox names. You retain those addresses and migrate to the Internet Mail Service by updating the e-mail addresses for the custom recipients and mailboxes in Microsoft Exchange Server with directory import. You need to update all the custom recipients after directory synchronization is completed the first time. If you don't replace custom recipients with mailboxes, you must update every mailbox as it is created on a Microsoft Exchange Server. If you ever change the site's e-mail addressing properties, update all the mailboxes in the site.

   To create the import file for modifying all the custom recipients

1. Create a text file with this header:

Obj-Class,Common-Name,Target-Address,Proxy-Addresses

2. Use the Directory Export command to export custom recipients to the text file.
3. Modify the proxy-addresses field based on the target-address field without changing X.400 and other address types. This can be done with a macro or a custom program.
Important    Microsoft Excel and other spreadsheet programs have a 256-character limit per cell. The proxy-addresses field can have more than 256 characters. Do not import the directory export file into Microsoft Excel or any other spreadsheet with this limitation because any characters beyond the first 256 are truncated and lost without warning. Use a database program such as Microsoft Access or Microsoft Visual FoxPro(tm) to get around this limitation.

4. Save the modified file in CSV format.
5. If the modified file's proxy-addresses field contains all the e-mail addresses for the recipient, use directory import with the Overwrite option selected in the Directory Import dialog box.
- or - If the modified file's proxy-addresses field contains just the new SMTP e-mail address for the recipient, use directory import with the Append option selected in the Directory Import dialog box.

The DNS can now be updated to route all mail for this domain to the Internet Mail Service instead of to the SMTP gateway. The Internet Mail Service resolves each address as belonging to a Microsoft Exchange Server recipient ¾ mailbox, custom recipient, public folder, and so on ¾ and routes the mail accordingly. When the SMTP gateway stops receiving mail, you know this change has been made in the DNS.

Next, the other postoffices need to have the access component reinstalled to route outbound SMTP mail to the Microsoft Mail Connector postoffice. Migration to the Internet Mail Service is now complete.

As mailboxes are migrated from Microsoft Mail postoffices, the custom recipient for the mailbox is removed, and a mailbox is created. If you have this configured to replace the custom recipients with mailboxes, the e-mail addresses are preserved.

Otherwise, the mailboxes should have their e-mail address updated as they are created or immediately thereafter. This can be done as part of the migration user list file or as a separate directory import file. To get the correct e-mail addresses, use directory export to create a file of custom recipients and their correct e-mail addresses before you begin to migrate mailboxes.

Maintaining External Addressing Conventions

Some Microsoft Mail networks have a host with an alias table which maps a simple external SMTP address to the more complex address that the SMTP gateway understands. For example, if external mailboxes have simple addresses, such as name@domain, the mapping table converts them to mailbox@postoffice.network.domain.

You can switch to that simpler address when migrating to the Internet Mail Service. This preserves the addresses that your users and their correspondents are used to. You need to use the Directory Export and Directory Import commands to modify the e-mail addresses of custom recipients and migrated mailboxes.

The difference between this scenario and the previous one is that the source of the new e-mail address is the alias table. After modifying all recipient addresses in Microsoft Exchange Server, the MX record in the DNS can be modified and the alias table removed. After this is done, the postoffices can have their gateway access component removed and reinstalled as needed.

Migrating to Microsoft Exchange Server and Using an SMTP Gateway

If you migrate mailboxes to Microsoft Exchange Server before installing the Internet Mail Service, you can configure your system to allow Microsoft Exchange Server users to use the SMTP gateway. Install an access component on the Microsoft Mail Connector postoffice pointing to the Microsoft Mail postoffice with the gateway, and configure the Microsoft Mail Connector address space to route mail sent to SMTP from Microsoft Exchange Server.

Because routing in Microsoft Mail is based on network and postoffice names, routing mail to Microsoft Exchange Server mailboxes is handled in one of the following ways:

Situation	Addressing solution
Using an alias table on SMTP host to map friendly addresses to Microsoft Mail gateway SMTP addresses.	Change the alias table to route mail to the appropriate Microsoft Exchange Server mailbox's MS type e-mail address.
Migrating partial postoffices and not using an alias table.	Microsoft Exchange Server mailboxes have a new SMTP address based on the Microsoft Mail Connector network and postoffice name.
Migrating entire postoffices and preserving Microsoft Mail type and SMTP e-mail addresses on migrated mailboxes. No alias table is used.	The old SMTP addresses route to the new Microsoft Exchange Server mailboxes without modifying the SMTP address.

Command-Line Options

This section consists of an alphabetical list of the SMTPGATE program options and how those features are set or utilized in the Internet Mail Service.

Command line:	In the Internet Mail Service use:
-BDmm-dd-yy -BThh:mm -BRdd:hh:mm	The Internet Mail Service runs continuously and does not support these features.
-C[newdi]	Logging is controlled from the Administrator program.
-Dd	No longer needed.
-G[acnsy]	No equivalent.
-H	Help on the Internet Mail Service is available in the Administrator's Program.
-HA	By recipient instead. See MAPI Recipient checkbox on Advanced property sheet of the recipient.
-I<size>	No equivalent.
-L[acnsy] -MR -MS	Logging is now controlled in the Administrator Program. Set in the Diagnostic Logging property page. Set in the Diagnostic Logging property page.
-MD	No longer needed.
-O<size>	Set in the General property page.
-Qnnn	Set in the General property page.
-P0nn	No longer needed.
-RE	No longer needed.
-RR
-T
-V20	No longer needed.
-Wnnn	Set in the Connections property page.
-X	No longer needed.

Migrating from an X.400 Gateway to an X.400 Connector

The Microsoft Exchange Server MTA can be used to replace an existing Microsoft Mail (PC) X.400 gateway. Users of Microsoft Mail for PC and AppleTalk networks can take advantage of the X.400 Connector. The following requirements must be met before you can migrate from the Microsoft Mail X.400 gateway to the Microsoft Exchange Server MTA:

• Mail addressed with the global address list and sent between Microsoft Mail postoffices and Microsoft Exchange Server computers is routed and delivered without any problems. The easiest way to do this is to connect the two systems with the Microsoft Mail Connector, but any connection method can be used.
• All Microsoft Mail mailboxes that will send or receive mail through the X.400 MTA and want something other than a default address must be in the Microsoft Exchange Server global address list as custom recipients. The easiest way to do this is to configure directory synchronization and wait for the custom recipients to be created.
• The X.400 Connector is configured and tested on a server in any site in the organization. Mail sent from Microsoft Exchange Server mailboxes is delivered to the X.400 system. Do not configure the connector to accept all incoming mail from your private management domain (PRMD) at this time. Just set up a narrow address space for testing.
• All Microsoft Mail postoffices must have access components for the X.400 gateway.

After these conditions have been met, make adjustments to addressing and routing before the gateway is shut down and the use of the gateway is migrated. This process depends on your configuration.

Addressing Schemes

How you migrate to using the X.400 MTA depends on how you were using the X.400 gateway and how you plan to use the X.400 MTA. Every Microsoft Exchange Server recipient has one X.400 e-mail address. This address can be replaced or supplemented with other X.400 e-mail addresses. You should configure the site's X.400 addressing system before beginning to migrate mailboxes. The following table summarizes the four possible approaches.

Addressing configured with an X.400 gateway	Addressing configured with an X.400 MTA	Method
Customized address maps and/or conversion strings.	Switch to default for site.	Switch address convention.
Customized address maps.	Preserve addresses for migrated users.	Maintain mapped addresses.
Mixture of customized address maps and address conversion strings.	Preserve addresses for migrated users.	Maintain mixed addresses.

One common strategy that the last three methods share is how to handle multiple X.400 addresses for one mailbox. The X.400 gateway supported this feature by having address mapping tables to convert X.400 addresses to Microsoft Mail addresses. The Microsoft Exchange Server MTA does not convert addresses; it looks them up in the directory. Since each recipient can have multiple X.400 type addresses, the Microsoft Exchange Server directory needs all the X.400 addresses for each recipient.

Maintaining Internal Address Conventions

By default, the X.400 gateway creates addresses for all Microsoft Mail mailboxes based on their network, postoffice, and mailbox names. You retain those addresses and migrate to the X.400 Connector by updating the e-mail addresses for the custom recipients and mailboxes in Microsoft Exchange Server with directory import. You need to update all the custom recipients after directory synchronization is completed the first time. If you don't replace custom recipients with mailboxes, you must update every mailbox as it is created on a Microsoft Exchange Server. If you ever change the site's e-mail addressing properties, update all the mailboxes in the site.

   To create the import file for modifying all the custom recipients

1. Create a text file with this header:

Obj-Class,Common-Name,Target-Address,Proxy-Addresses

2. Use the Directory Export command to export custom recipients to the text file.
3. Modify the proxy-addresses field based on the target-address field without changing SMTP and other address types. This can be done with a macro or a custom program.
Important    Microsoft Excel and other spreadsheet programs have a 256-character limit per cell. The proxy-addresses field can have more than 256 characters. Do not import the directory export file into Microsoft Excel or any other spreadsheet with this limitation because any characters beyond the first 256 are truncated and lost without warning. Use a database program such as Microsoft Access or Microsoft Visual FoxPro to get around this limitation.

4. Save the modified file in CSV format.
5. If the modified file's proxy-addresses field contains all the e-mail addresses for the recipient, use directory import with the Overwrite option selected in the Directory Import dialog box.
- or - If the modified file's proxy-addresses field contains just the new X.400 e-mail address for the recipient, use directory import with the Append option selected in the Directory Import dialog box.

As mailboxes are migrated from Microsoft Mail postoffices, the custom recipient for the mailbox is removed, and a mailbox is created. If you have this configured to replace the custom recipients with mailboxes, the e-mail addresses are preserved.

Otherwise, the mailboxes should have their e-mail address updated as they are created or immediately thereafter. This can be done as part of the migration user list file or as a separate directory import file. To get the correct e-mail addresses, use directory export to create a file of custom recipients and their correct e-mail addresses before you begin to migrate mailboxes.

Switching Address Conventions

You can change to a company standard naming convention for your X.400 addresses as part of migrating to Microsoft Exchange Server. Your users that receive mail with their current X.400 address need to let their correspondents know their new address. The address is created based on the structure you define in the Site Addressing property page.

This is the easiest way to handle addressing conversion. The X.400 MTA has a connector configured to your administrative management domain (ADMD), and the X.400 gateway is brought down. All the postoffices that need to route X.400 mail a different way have their indirect access component reinstalled to route mail to the Microsoft Exchange Connector postoffice. Send a message containing new address information to each Microsoft Mail user once the conversion is complete.

X.400 users who cannot receive mail that is returned as undeliverable as a result of the address change can have secondary e-mail addresses created for them using their old address.

Coexistence with the AT&T Gateway and the Internet Mail Service

Microsoft Mail for PC Networks versions 3.2 and 3.5 included the AT&T gateway. The following table presents some ways to configure coexistence during migration.

Gateways and Connectors	Approach	Results
AT&T only	Install access component on Microsoft Exchange Connector postoffice. Set address space to SMTP.	Microsoft Exchange Server and Microsoft Mail (PC) mailboxes can send and receive mail through the gateway.
AT&T and Internet Mail Connector	Install access component on Microsoft Exchange Connector postoffice. Set in the General property page. Set address space for AT&T to SMTP with a cost of 100. Set address space on Internet Mail Service to SMTP:*@* with a cost of 0.	Microsoft Exchange Server and Microsoft Mail (PC) mailboxes can send and receive mail through the AT&T gateway. Microsoft Mail (PC) users can only receive mail from the Internet Mail Service.
AT&T version 1.1 and SMTP with address preprocessor	Install access component on MS Mail Connector postoffice. Set address space in Microsoft Exchange server for connector to SMTP.	Microsoft Exchange Server and Microsoft Mail (PC) mailboxes can send and receive mail through both gateways.
Internet Mail Service, AT&T, and SMTP with address preprocessor	Install access component on Microsoft Exchange Connector postoffice. Set address space for AT&T to SMTP with a cost of 100. Set address space on Internet Mail Service to SMTP:*@* with a cost of 0.	Microsoft Exchange Server and Microsoft Mail (PC) mailboxes can send and receive mail through the AT&T gateway. Microsoft Mail (PC) users can send mail out through the SMTP gateway and receive mail from the SMTP gateway or Internet Mail Service. Microsoft Exchange server users can mail out the Internet Mail Service and receive mail from the SMTP gateway or the Internet Mail Service.

Depending on the approach you take, you might need to examine preserving addresses for migrated mailboxes.