Mail Routing with GWMTP Enabled

Now that you understand the concepts behind GroupWise GWMTP in conjunction with Internet addressing, this section discusses the flow of email through a GWMTP and Internet addressingenabled GroupWise system.

Outbound Email

Internet addressingaware (or IA-aware) clients (GroupWise 5.5x and newer clients) allow mail with Internet addresses to be routed internally or to Internet users without the use of addressing rules or external domain definitions. Without Internet addressing enabled (and no addressing rules in use), messages sent to users with Internet-style addresses are flagged as undeliverable when mail is sent from the client.

With Internet addressing enabled, the client performs less lookup on recipient addresses. Messages with Internet-style addresses are pushed on by the client to be resolved by the POA, MTA, or GWIA. Note, though, that each component in an Internet addressing-aware GroupWise system is capable of parsing Internet address information to some extent, including the GroupWise client. Each component (client, POA, MTA, and GWIA) will do the best it can to resolve the address from its perspective.

If the POA cannot resolve an address, it pushes the message to the domain MTA. If the message is addressed to an Internet address, and the domain MTA cannot resolve the message to one of its post offices, or internal to the system, it will route the message to the default routing domain for a GWMTP lookup by the MTA there. If the recipient address cannot be resolved with a GWMTP DNS lookup, the message will be routed to the default GWIA for transfer to the Internet.

Inbound Email

When a message arrives at a GroupWise system from the outside world, it does so in one of two ways:

• Direct MTA-to-MTA transfer via GWMTP

• SMTP/MIME transfer via the GWIA

Note

Messages can also come in through another GroupWise gateway, but typically those are not going to be outside-world messages. Most other gateways, such as the Exchange gateway or the Lotus Notes gateway, are handing explicitly addressed messages to the GroupWise MTA, so the messages can be treated as internal to the GroupWise system.

When a message comes in via GWMTP, the MTA receiving the message will process the message by sending it to the GroupWise domain within the GroupWise system of which the recipient is a member. The recipient's domain routes the message to the recipient's POA, which delivers the message to the recipient's mailbox.

Messages can of course also be delivered via the GWIA. This message flow is described in more detail in Chapter 16.

Naming Conventions

Naming conventions are important for both GWMTP and native Internet addressing via the GWIA. In Chapter 16 see the section "Naming Conventions" for some recommendations.

System Design

This section offers a few suggestions on effectively setting up GroupWise Internet addressing on your GroupWise system:

• If direct MTA-to-MTA connectivity is enabled, the GroupWise domain that owns the default GWIA should be the default routing domain. This will simplify firewall administration (only one machine needs to be outside the firewall) and reduce traffic.

• On large systems that span wide area networks, use default GWIA and default routing domain overrides to ensure that traffic bound to the Internet takes the most efficient route. (This assumes that your system has more than one connection to the Internet.)

• Ensure that all GWMTP-enabled MTAs can receive packets from their assigned port from the Internet and that they can send packets out to the Internet on high-numbered ports.

These system design suggestions are most relevant in large GroupWise systems (5,000 or more), of which there are many!