Usenet news and mailing lists constantly remind us of each other. And the
parallels are so strong that many mailing lists are gatewayed two-way
with corresponding Usenet newsgroups, in the bit hierarchy
which maps onto the old BITNET, and elsewhere.
There are probably ten different situations where a mailing list is
better, and ten others where the newsgroup approach works better. The
point to recognise is that the system administrator needs a choice of
gatewaying one with the other, whenever tradeoffs justify it. Instead
of getting into the tradeoffs themselves, this chapter will then focus
on the mechanisms of gatewaying the two worlds.
One clear and recurring use we find for this gatewaying is for mailing
lists which are of general use to many employees in a corporate network.
For instance, in stockbroking company, many employees may like to
subscribe to a business news mailing list. If each employee had to
subscribe to the mailing list independently, it would waste mail spool
area and perhaps bandwidth. In such situations, we receive the mailing
list into an internal newsgroup, so that individual mailboxes are not
overloaded. Everyone can then read the newsgroup, and messages are also
archived till expired.
In CNews, this is trivially done by adding one line to the
sys file, defining a new outgoing feed listing all the
relevant groups and distributions, and specifying the commandline to be executed
which is supposed to send out the outgoing message to that ``feed.'' This
command, in our case, should be a mail-sending program,
e.g.
/bin/mail user at somewhere.com. This is often adequate to get
the job done. We are sure almost every Usenet news software system will have
an equally easy way of piping the feed of a newsgroup to an email address.
With our Usenet software sources has been integrated a set of
scripts which we have been using for at least five years internally.
This set of scripts is called mail2news. It contains
one shellscript called mail2news, which takes an
email message from stdin, processes it, and feeds the
processed version to inews, the
stdin-based news article injection utility of C-News.
The inews utility accepts a new article post in its
stdin and queues it for digestion by
newsrun whenever it runs next.
To use mail2news, we assume you are using
Sendmail to process incoming email. Our instructions can easily be
modified to adapt to any Mail Transport Agent (MTA) of your choice. You
will have to configure Sendmail or any other MTA to redirect incoming
mails for the gateway to a program called m2nmailer,
a Perlscript which accepts the incoming message in its standard input
and a list of newsgroup names, space separated, on its command line.
Sendmail can be easily configured to trigger m2nmailer
this way by defining a new mailer in sendmail.cf,
and directing all incoming emails meant for the Usenet news system to
this mailer. Once you set up the appropriate rulesets for Sendmail,
it automatically triggers m2nmailer each time an
incoming email comes for the mail2news
gateway.
The precise configuration changes to Sendmail have already been
specified in the chapter titled ``Setting up C-News + NNTPd.''
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