The submit(ADM) command uses the domain tables for two purposes: to specify the fully qualified host name and (optionally) to specify the route to a host by listing the fully qualified host names of one or more intermediate hosts through which mail is to be routed.
First, submit separates the fully qualified host name into two parts: the name of the domain table and the host name to match on the left-hand side of the entries in the domain table. For example, in the address email@example.com, the name of the domain table to search is canada.com and the host name to search for is engr.
MMDF tests an address for matches against the domain names in the MDMN entries in mmdftailor. For example, the address firstname.lastname@example.org matches this MDMN entry:
MDMN "canada.com", show="Canada Delivery", tbl=canadadomThen, MMDF searches mmdftailor for the MTBL entry for canadadom:
MTBL canadadom, file="canada.dom", show "Canada Delivery"MMDF uses the file associated with canadadom (canada.dom).
Thus, to route our message to email@example.com, submit uses this algorithm to search the domain tables for a match in the address:
The flags=route parameter in the MTBL entry enables that table entry to match addresses for an entire subdomain, acting as a gateway. Do not use flags=route on tables other than the root domain table unless you have internal subdomains.
Use the flags=partial parameter on the local domain table so that users do not have to specify the full domain to send mail on the local machine.
If the address provided is username@host (for example, david@engr), MMDF performs the same search as described above except that there is no canada.com to match in the MDMN entries in mmdftailor. In this case, MMDF searches the root domain table and then the tables that include flags=partial in the MDMN line.