Mail2News Mini-Howto
Robert Hart, InterWeft IT Consultants Melbourne, Australia
iweft@ipax.com.au
v1.0, 4 November 1996
This document describes how to set up your news server and the
mail2news.pl software to link mailing lists to local news groups.
1. Copyright and such
The copyright of this document is retained by the author. Permission
is granted to distribute the document by electronic means and on CDs
provided that it is kept entirely in its original format. Permission
is also granted to print a copy of this document for personal use.
The republishing of this document in part or in whole without the
permission of the copyright holder by any means other than as noted
above is prohibited.
This document is directly supported by InterWeft IT Consultants
(Melbourne, Australia).
The latest version of this document is available at the InterWeft WWW
site at InterWeft IT Consultants <http://203.29.72.65/>.
2. Introduction
Most Internet sites are always seeking ways to improve the usage of
the limited bandwidth awailable across their link to the Internet.
Should more than one user subscribe to the same mailing list, there is
going to be traffic duplication. If there are a number of such
duplications - or the traffic on the lists is high, the consumption of
bandwidth increases.
By subscribing the site to a list (if this is allowed by the list
owner) and 'gating' the email traffic to the local news server, it is
possible to make mailing lists accessible to all site users, or, using
the security features of 'innd', to limit the access to certain users.
Such a site subscription (particularly if there are a number of high
traffic lists) can make worthwhile savings in bandwidth usage.
Reading list traffic in news reader also offers users the advantages
of threading (which is not available in many mail user agents) and
keeps their mail 'inbox' free for possibly more urgent, personal
email.
This mini-HOWTO describes setting up the 'mail2news.pl' script to
accomplish this.
2.1. Finding mail2news.pl
The author has been unable to find mail2news.pl on CPAN (the
Comprehensive Perl Archive Network) - but it may just have been
overlooked. It is however on sunsite.unc.edu - somewhere - and also on
ftp.redhat.com.
As this Perl script is not lengthy, it is appended to this howto.
3. Overview of the system
It is probably easiest to understand how this system works by tracking
a message from the mailing list to the newsgroup and then a message
posted to the local newsgroup (gated to the mailing list) and see how
they are handled.
3.1. Mail from the mailing list
Mail from the mailing list is sent to all subscribed mail addresses. A
special mail alias is subscribed to the mailing list in question and
so all traffic to and from the list is sent by the list server to this
address.
When mail from the mailing list arrives at the local machine, the mail
alias pipes the incoming message to mail2news.pl. The mail alias also
specifies the destination (local) newsgroup.
The mail2news.pl script processes the message, applying news headers
and then uses rnews or inews to post the message to the newsgroup.
3.2. Messages posted to the local newsgroup
The local newsgroup is set up as a moderated group, as this allows us
to take advantage of the email capabilities of innd. Any messages
posted to a moderated group are not immediately submitted to the
group. Instead, messages are emailed to the moderator of the group.
By declaring the moderator of the local newsgroup to be mailing list
address, all locally posted messages to the newsgroup are
automatically mailed out to the mailing list by innd and only appear
once they have been received back through mail2news.pl which adds the
necessary 'approved' line to the messages and are thus acceptable to
innd for posting to the newsgroup.
4. Setting up mail2news
Put the mail2news.pl script in a suitable location. I favour
/usr/local/scripts, but the location is up to you.
You will need to edit script as follows:-
� At the top of the script, make sure you are pointing at the local
Perl binary
___________________________________________________________________
#!/usr/bin/perl
# point at the correct location of perl
___________________________________________________________________
� I had problems with the three following lines. Commenting them out
does not cause a problem.
___________________________________________________________________
( $version ) = $] =~ /(\d+\.\d+).*\nPatch level/;
die "$program: requires at least version 3 of perl\n"
if $version < 3;
___________________________________________________________________
� Edit the following lines to point at the posting program (I use
rnews) and you news host:-
___________________________________________________________________
# $inews = "/usr/bin/inews";
# $iopts = "-h -o \"mail2news gateway\"";
$inews = "/usr/bin/rnews";
$iopts = "";
$postinghost = "your.news.server"; # points at your news server
___________________________________________________________________
� Make sure that the script is exectuable (mode 755).
5. Establishing the mail aliases
Edit /etc/aliases to create entries for the mailing list(s) you wish
to pipe into news. Each entry should be of the form:-
______________________________________________________________________
<subscribed email address to list>: \
"| /usr/local/scripts/mail2news.pl <local news group name>"
<code>
<p>
So for example if the email address to which email from the list is to
be sent (the subscribed mail address) is <tt/site_list/ and the local
newsgroup to which mail is to be posted is <tt/local.site.group/, the
alias would be
<code>
# The site subscription address for blah-blah@some.mailing.list
site_list: "| /usr/local/scripts/mail2news.pl local.site.group"
______________________________________________________________________
Make an entry for each mailing list that is to be gated to oyur local
news server and and then run newaliases.
6. Setting up the news groups and news server (innd)
Using ctlinnd, create the newsgroups on your news server. Remember,
these are to be local news groups, so start them with a distinctive
name so you can filter them out from your news distributions (in your
newsfeeds file).
You also need to tell innd that the group is moderated (by using
ctlinnd). Remember, innd is very sensitive to file ownership and
permissions, so you need to interct at this level with innd as the
news user. Indicating a moderated group is done by specifying m to the
newgroup command.
______________________________________________________________________
ctlinnd newgroup <newgroup name> m <newsadmin>
______________________________________________________________________
The m tells innd that the group is moderated.
Edit your newsfeeds file to make sure that these local groups are not
distributed (unless you specificaly wish this to occur).
For example, if your mailing list is called local.site.group, then you
would probably want to add !local* to the second field of your up (and
possibly your down) stream news sites in your newsfeeds file.
Now, in order to ensure that user messages are sent to the list
automatically by innd, edit /etc/news/moderators to include a line
declaring the mailing list email address as the moderator.
______________________________________________________________________
some.site.list:list@mail.list.site
______________________________________________________________________
7. Subscribing the mail2 news alias to the mailing list
You now need to subscribe the mail alias to the mailing list. Check
with the mailing list information as to how to subscribe. Some mailing
lists allow you to subscribe an email address that is different from
the address from which the subscription comes (they check back to the
address to be subscribed for confirmation before actually subscribing
that address).
Other mailing lists do not permit this. So you may need to 'forge' a
subscription request. There are many ways of doing this. One of the
easiest is to use Netscape mail set up (temporarily) with the address
to which the mailing list is to send the mail.
After subscribing, you should see a 'welcome' message of some kind
from the list server in the news group - in which case all is well and
you can now test the other direction by posting a news message to your
new list.
The message should *NOT* appear in the newsgroup at once. It should
get sent out by mail and then received back and posted to the news
group.
If this works, you have succeed in getting the list gated to news.
8. If it doesn't work...
If things don't work, you need to track through the path the messages
are taking to see exactly where things are breaking down. Useful tools
here are the mail and news logs.
Robert Hart
Melbourne, Victoria, Australia October 1996
9. The mail2news.pl script
______________________________________________________________________
#!/usr/bin/perl
($program = $0) =~ s%.*/%%;
#( $version ) = $] =~ /(\d+\.\d+).*\nPatch level/;
#die "$program: requires at least version 3 of perl\n"
# if $version < 3;
# $inews = "/usr/bin/inews";
# $iopts = "-h -o \"mail2news gateway\"";
$inews = "/usr/bin/rnews";
$iopts = "";
$postinghost = "your.news.server";
if ($#ARGV < 0) {
# $newsgroup = "test";
# we'll expect the newsgroup line in the body
} elsif ($#ARGV == 0) {
$newsgroup = $ARGV[0];
} else {
die "usage: $program [newsgroup]\n";
}
# in case inews dumps core or something crazy
$SIG{'PIPE'} = "plumber";
sub plumber { die "$program: \"$inews\" died prematurely!\n"; }
open (INEWS, "| $inews $iopts") ||
die "$program: can't run $inews\n";
# header munging loop
while (<STDIN>) {
last if /^$/;
# transform real from: line back to icky style
s/^From:\s+(.*) <(.*)>/From: $2 ($1)/;
s/Message-Id/Message-ID/;
# transform from_ line to path header; also works locally
s/^From\s+(\S+)@(\S+).*/Path: $2!$1/
|| s/^From\s+(\S+)[^@]*$/Path: $1\n/;
print INEWS
# if /^(Date|From|Subject|Path|Newsgroups|Organization|Message-ID):/i;
if /^(Date|From|Subject|Path|Newsgroups|Message-ID):/i;
$saw_subject |= ( $+ eq 'Subject' );
$saw_msgid |= ( $+ eq 'Message-ID' );
# $saw_newsgroup |= ( $+ eq 'Newsgroups' );
}
warn "$program: didn't expect newsgroup in both headers and ARGV\n"
if $newsgroup && $saw_newsgroup;
die "$program: didn't get newsgroup from either headers or ARGV\n"
unless $newsgroup || $saw_newsgroup;
$approved = $newsgroup;
$approved =~ s/\./'-'/eg;
($sec,$min,$hour,$mday,$mon,$year)=localtime(time);
$madeupid = "\<$year$mon$mday.$hour$min$sec.$$\@kepler.hedland.edu.au\>";
printf INEWS "Newsgroups: %s\n", $newsgroup if $newsgroup;
printf INEWS "Approved: %s\@kepler.hedland.edu.au\n", $approved;
print INEWS "Subject: Untitled\n" unless $saw_subject;
printf INEWS "Message-ID: %s\n", $madeupid unless $saw_msgid;
printf INEWS "NNTP-Posting-Host: %s\n", $postinghost;
print INEWS "Organisation: (mail2news gateway)\n";
print INEWS "\n";
print INEWS while <STDIN>; # gobble rest of message
close INEWS;
exit $?;
______________________________________________________________________