Message Delivery

After the message is processed, the master program sends the message to the next stop along the message’s delivery path. This may be the intended recipient’s mailbox, another MTA, or even a different channel. Forwarding to another channel is not shown in the picture, but is common occurrence.

Note that the local parts of addresses and received fields are typically 7-bit characters. If the MTA reads 8-bit characters in the in these fields, it replaces each 8-bit character with asterisks.