PLANNING
When you set up the first IBM® Domino server, the setup program creates your Domino domain's Domino Directory. Each server in the domain stores a replica of the Domain's Domino Directory. Domino replication synchronizes the Domino Directories on each server.
In addition to the Domino Directory, Domino retrieves information from the server's NOTES.INI file and, when routing mail over SMTP, from the Domain Name System (DNS), which is maintained separately.
The Domino Directory supports LDAP so that Internet mail clients can use LDAP to query and modify the directory if they have access to do so.
For ease of maintenance, when entering server information in the Domino Directory, refer to the server by its fully-qualified host name rather than its IP address. Although Domino fully supports IP addresses, host names are less subject to change than numeric addresses. For example, for TCP/IP to work properly a server's numeric IP address must change if you move the server to a new subnet, or have to merge two networks as the result of reorganization. Using a host name in the same documents, on the other hand, would not require any update.
Domino routing tables
A routing table is a list of connections from a Domino server to all other servers it can contact. Domino uses the routing table to determine the best, least-cost path to deliver mail. When you start the router on a server, it gathers information from the NOTES.INI file, and the Configuration Settings, Connection, Domain, and Server documents in the Domino Directory to build a dynamic routing table.
The router automatically recalculates the routing table after you reboot the server or restart the router task. In addition, the router checks the Domino Directory for changes at intervals of approximately five minutes. If it detects changes in these source documents, it rebuilds the routing table to incorporate the new information.
You can use a TELL command to refresh the routing table without having to restart the router. The ability to update the routing table on demand is especially useful when testing new configuration settings.
How the router uses the Domino Directory to look up mail recipients
When a user sends mail to a recipient in the local domain, the router looks up the complete address in the ($Users) view of the Domino Directory (if you set up Directory Assistance, the router can also look up the address in a secondary directory) for the recipient's Person document, which lists the recipient's home server. If the recipient's home server is the current server, the router will deliver the message. If it is a different server, the router consults the routing table to determine the best route, or least-cost path, for transferring the message to the destination home server and routes the message along that path.
If the router cannot find a match for the recipient in the specified directories, it can forward the message to a "smart host," which is a server that has a directory of users who are in the local domain but who are not listed in the Domino Directory. For example, if you are migrating users from a UNIX™ sendmail system to a Domino mail system but you have not migrated all users yet, you set up a UNIX server as a smart host that can locate the sendmail users and route mail to them. Enter the name of the smart host in the Local Internet domain smart host field on the router/SMTP-Basics tab of the Configuration Settings document.
Documents used for routing mail
The Domino Directory uses numerous documents to define the messaging topology. Depending on your needs, you may need to create or edit the following documents:
Table 1. Routing Document Names and Descriptions
Related concepts Messaging overview Overview of routing mail using Notes routing The Domain Name System (DNS) and SMTP mail routing The Domino Directory Setting up the LDAP service Setting up the Domino Directory for a domain Directory catalogs Directory assistance
Related tasks Recalculating the server's routing table