[Mimedefang] allow local aliases w/ md_check_against_smtp_server

[Ron Peterson]

On Tue, Sep 21, 2004 at 09:17:54AM -0400, David F. Skoll wrote:
> On Tue, 21 Sep 2004, Ron Peterson wrote:
> 
> > Yeah, I thought about that, but it just seems silly to be reading
> > /etc/aliases over and over every time a new message comes in (this is a
> > pretty busy server, too).
> 
> So do it once per slave, in filter_initialize.  (Unless your aliases
> file changes often.)
> 
> Or better yet, use the Berkeley DB lookup functions to access the alias
> DB directly.

Thanks.  Saved me some head scratching.  Didn't know about
filter_initialize.  That's the method I used - works great.  The db
lookup would immediately respond to 'newaliases' updates, but I thought
this would be overall faster.  Probably should let the computer work a
little harder so I can be a little lazier, I suppose..

I needed something like this to implement mailman on our our email
gateway.

my %MAIL_ALIAS;
sub init_aliases_hash () {
    open( MAIL_ALIASES, "</etc/aliases" ) or die "Can't read /etc/aliases: $!\n";
    my $alias;
    while( <MAIL_ALIASES> ) {
        chomp;
        next if /^#/;
        next unless /\S+/;
        ($alias, $val) = $_ =~ /(.*?):(.*)/;
        $MAIL_ALIAS{$alias} = $val;
    }
    close( MAIL_ALIASES );
}

# Called each time a new slave starts.
sub filter_initialize () {
    # we can then refer to %MAIL_ALIAS in filter_recipient, below.
    init_aliases_hash();
}

sub filter_recipient {
    my($recip, $sender, $ip, $host, $first, $helo,
       $rcpt_mailer, $rcpt_host, $rcpt_addr) = @_;

    my( $sendto );
    ($sendto) = $recip =~ /<(.*?)\@.*/;

    ...

    if( ! $MAIL_ALIAS{$sendto} ) {
        return md_check_against_smtp_server($sender, $recip,
                                            "mgate.mtholyoke.edu",
                                            "mail.mtholyoke.edu");
    } else {
        return 1;
    }
}

-- 
Ron Peterson
Network & Systems Manager
Mount Holyoke College