Amavis Postfix and Altermime

From Wickle Wiki

This is a document about installing a mail server who checks for virus, spam and it insert a disclaimer on every outgoing message. Simple , isn't ??

[edit]

Resume

First of all we must have a working copy of postfix. thats simnple because postfix is installed from apt-get or rpm easily. To doing that you must MODIFY amavisd-new DAEMON

After that , install amavisd-new (i installed it easily from apt-get)

Them configure postfix to use it : Relevant parts of main.cf:

content_filter = smtp-amavis:[127.0.0.1]:10024

Relevant parts of master.cf :

smtp      inet  n       -       -       -       -       smtpd
smtp-amavis unix        -       -       n       -       2       smtp
        -o smtp_data_done_timeout=1200
        -o smtp_send_xforward_command=yes
        -o disable_dns_lookups=yes
127.0.0.1:10025 inet n  -       n     -       -  smtpd
         -o content_filter=
         -o smtp_send_xforward_command=yes
         -o local_recipient_maps=
         -o relay_recipient_maps=
         -o smtpd_restriction_classes=
         -o smtpd_client_restrictions=
         -o smtpd_helo_restrictions=
         -o smtpd_sender_restrictions=
         -o smtpd_recipient_restrictions=permit_mynetworks,reject
         -o mynetworks=127.0.0.0/8
         -o strict_rfc821_envelopes=yes
         -o smtpd_error_sleep_time=0
         -o smtpd_soft_error_limit=1001
         -o smtpd_hard_error_limit=1000

Now , restart amavis, restart postfix and try it logs are on /var/log/amavis.log

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Installing altermime

You can install altermime from apt, or downloading it from http://www.pldaniels.com/altermime/

you must configure and make it, them install (i have it under /usr/local/bin) them we will modify amavisd-new daemon to insert a disclaimer on every outgoing mail.

This is the code, insert it on the line 5740, just before :

# THIRD: now that we know what to do with it, do it!

        if ($forward_method ne '') {  # message must be delivered explicitly

Code:

            my $sender = $msginfo->sender;
            my $is_outgoing = lookup($sender, \@local_domains_acl);
#           $is_outgoing=1;
            do_log(1,"dominio: @local_domains_acl");
            do_log(1,"is_outgoing ? sender: $sender, result: $is_outgoing");
            # Add disclaimer
            if ($is_outgoing)  {
                my $disc_bypass = 0;
                my $res = 0;
                my($hdr_edits) = $msginfo->header_edits;
                $hdr_edits = Amavis::Out::EditHeader->new() if ! $hdr_edits;
                do_log(1,"ok, not yet in message, add disclaimer to message");
                $hdr_edits->append_header('X-Disclaimer-NNA','Disclaimer added elprogreso.com');

                # add Disclaimer to message
                $fh->close() or die "Can't close file to run altermime: $!";
                my $cmd = "/usr/local/bin/altermime --input=$tempdir/email.txt --disclaimer=/etc/postfix/disclaimer.txt";
                $cmd .= " --disclaimer-html=/etc/postfix/disclaimer.txt";
                #Actually run the command
                system($cmd);
                $fh = IO::File->new("$tempdir/email.txt") or die "Can't reopen altermimed file: $!";
                $fh->seek(0,0) or die "Can't rewind mail file (9): $!";
                binmode($fh,":bytes") or die "Can't cancel :utf8 mode: $!"  if $unicode_aware;
                $msginfo->mail_text($fh);
                # save headers
                $msginfo->header_edits($hdr_edits);
                do_log(1,"-------- DISCLAIMER ANADIDO");
            } else {
                do_log(5,"NO Disclaimer - From:<$sender> isn't local");
            }

and after :

            $which_section = "forwarding";
            ensure_mime_entity($msginfo,$fh,$tempdir,\@virusname); #need header

To make this work well, the variable local_domains_acl on main.cf must be defined and pointing to all local domains.

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Alert the sender on remitent vacation

This is the script i use to alert a mail sender that the remitent is not on the office (on holidays for example) You need activate procmail, for example with this on main.cf:

mailbox_command = procmail -a "$EXTENSION"

and you need to put the file .procmailrc on the vacation home user:

PMDIR=$HOME

:0 Whc: vacation.lock

# The three (ANDed) conditions address the following:
# Reply if mail is addressed to me.
# Don't reply to daemons or mailing lists (! = not).
# Avoid mail loops (don't reply to mail I might send myself).

* $^To:.*\<$\LOGNAME\>
* !^FROM_DAEMON
* !^X-Loop: mymail@mydomain.com

# Store sender's address in vacation.cache if not there already.
| formail -rD 8192 vacation.cache

# If sender's address not in cache (e=previous recipe failed), send
# mail containing vacation message.  Note:  Trailing backslashes (\)
# required to denote continuation of single action line.

 :0 ehc
| (formail -rA"Precedence: junk" \
            -A"X-Loop: mymail@mydomain.com ; \
   cat $PMDIR/vacation.msg \
  ) | $SENDMAIL -oi -t

The file ~HOME/vacation.msg must exist and contains the message: