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- .SH
- Submit
- .PP
- For all the changes to its internals, the external interface of
- \fBsubmit\fR has changed remarkably little since MMDFI.
- The only notable external changes to \fBsubmit\fR are that it now
- processes domain-style addresses (both forward and reverse!)
- and both RFC822
- and RFC733 format addresses.
- .FN
- D. Crocker, J. Vittal, K. Pogran, D. Henderson, ``RFC733 - Standard
- for the Format of ARPA Network Text Message'',
- Network Information Center, SRI International, November 1977.
-
- D. Crocker, ``RFC822 - Standard
- for the Format of ARPA Network Text Message'',
- Network Information Center, SRI International, August 1982.
- .FE
- A couple of new options have been added to \fBsubmit\fR to give some
- control over the handling of returned mail in the event that a message
- cannot be delivered. This is
- useful if the user is a program and does not care if
- the message is undeliverable!
- It is also now possible to feed a bare message to \fBsubmit\fR and tell
- \fBsubmit\fR to find all the addresses and show them and their validity
- on a one-by-one basis. This makes it convenient
- to feed mail to \fBsubmit\fR from a smart mail composer that doesn't want to
- know how to parse addresses (a major task these days!).
- .PP
- The \fBsubmit\fR program can operate in one of two modes.
- In \fIprotocol\fR mode, \fBsubmit\fR accepts options, a return address,
- and optionally a list of addresses for each message, followed by the
- message text. Multiple messages can be submitted
- one after another without reinvoking the \fBsubmit\fR process.
- Each address is individually acknowledged. If there is an error,
- the submission of that letter is aborted and a new submission
- may be made.
- In \fIone-shot\fR mode a single message is submitted on the standard
- input.
- As in \fIprotocol\fR mode, it can be preceded by options and addresses,
- or the options can be given on the command line and the addresses taken
- from the message text.
- .PP
- The internal address verification process of \fBsubmit\fR has changed
- greatly since MMDFI. Most of the changes
- have been made to properly support domain style addresses.
- Additional changes were made to support per-channel
- and per-user access
- controls.
- While \fBsubmit\fR is checking each address, regardless
- of origin, it is also compiling the address
- list for the message.
- Each address list entry contains the destination domain,
- .FN
- By ``domain'' we mean the full domain specification of a host, e.g.
- VAX1.UDEL.ARPA.
- .FE
- the destination mailbox,
- and the channel in whose channel table \fBsubmit\fR first found the destination
- host.
- The lookup is somewhat complicated.
- The destination domain is looked up in the domain tables;
- the first entry found is used.
- Each domain table entry has associated with it the routing to be used to reach
- that domain/host. Normally this is just the name of the host itself
- if the host is directly accessible, but it can be a sequence of hosts if the
- destination is not directly accessible.
- This ``routing host'' is then looked up in the channel tables
- to find a channel which can reach it. The routing host specifications
- and the entries in the channel tables are always full domain specifications,
- so as to be unambiguous.
- .PP
- Authorization is checked after a valid channel for a host is found.
- Access to send via a given channel
- depends on the originating channel and/or the submitting user.
- If access to a given channel is denied, \fBsubmit\fR will continue to look
- at subsequent channels to see if some other channel has access to the
- same host and is authorized. This mechanism is commonly used
- to restrict access to expensive transport systems or to restrict
- message transfer between channels representing private and public
- data networks.
- It can also be used to restrict relaying of messages between two
- "controlled-access" networks.
-