The Domino Mail Router (Router) is a special server task responsible for the delivery and transfer of messages in MAIL.BOX.
- Delivery refers to moving messages from MAIL.BOX into a local mail file or database.
- Transfer refers to sending messages from MAIL.BOX to another server.
The Mail routing on a Domino server begins when a mail server receives a message from a mail client, from a Router on another Domino server, or from an application. The message is then transferred to a Lotus Notes Database, called MAIL.BOX, on the server. The server temporarily stores all inbound and outbound emails in the MAIL.BOX database.
The Router task periodically checks MAIL.BOX for new or altered messages. When it finds a message that requires processing,
- The Router reads the recipient list.
- Determines whether the destination mail file is on the current server or a different server.
- The Router then moves the message, delivers it to either local mail files on the server, or transfers it to MAIL.BOX databases on other servers as necessary.
When a recipient’s mail file is not located on the local server but is within the Domino domain, Domino calculates how to route the message to the recipient’s server and whether to use SMTP (Simple Mail Transfer Protocol) or Notes routing (NRPC). The message format and the configuration of the local server determine how Domino sends the message to the server. If the message is in MIME format, and the local server can use SMTP to send messages within the local Internet domain and the home mail server can receive SMTP, then the Router uses SMTP to send the message. Otherwise, the message is routed using NRPC.
The Router task converts the message format when necessary. Conversion can occur during both message delivery and message transfer. For instance, if a recipient’s Person document specifies that incoming emails should be stored in MIME format, but the original message was sent in Notes rich text format, then the Router converts the message to MIME format before delivering it to the local recipient’s mail file. To ensure that the receiving server can process MIME messages, the sending server checks the Server document of the recipient’s server to determine the version of Domino it’s running.