amavisd-milter(8) sendmail milter for amavisd-new

SYNOPSIS

[-fhv ] [-d debug-level ] [-D delivery-care-of ] [-m max-conns ] [-M max-wait ] [-p pidfile ] [-P ] [-q backlog ] [-s socket ] [-t timeout ] [-S socket ] [-T timeout ] [-w directory ]

DESCRIPTION

The is a sendmail milter (mail filter) for amavisd-new 2.4.3 and above and sendmail 8.13 and above (limited support for 8.12 is provided).

Instead of older amavis-milter helper program, full amavisd-new functionality is available, including adding spam and virus information header fields, modifying Subject, adding address extensions and removing certain recipients from delivery while delivering the same message to the rest.

For more information you can visit amavisd-milter website:

http://amavisd-milter.sourceforge.net/

and SourceForge project:

http://sourceforge.net/projects/amavisd-milter

Options

The options are as follows:

-d debug-level
Set the debug level to debug-level . Debugging traces become more verbose as the debug level increases. Maximum is 9.
-D delivery-care-of
Set AM.PDP request attribute delivery_care_of to client (default) or server . When client method is used then amavisd-milter is responsible to forward the message to recipients. This method doesn't allow personalized header or body modification.

When server method is used then amavisd-new is responsible to forward the message to recipients and can provide personalized header and body modification. $forward_method in amavisd.conf must point to some place willing to accept mail without further checking in amavisd-new .

-f
Run in the foreground (i.e. do not daemonize). Print debug messages to the terminal.
-h
Print help page and exit.
-m max-conns
Maximum concurrent amavisd connections (default 0 - unlimited number of connections). It must agree with the $max_servers entry in amavisd.conf.
-M max-wait
Maximum wait for connection to amavisd in seconds (default 300 = 5 minutes). It must be less then sending MTA timeout for a response to the final "." that terminates a message on sending MTA. sendmail has default value 1 hour, postfix 10 minutes and qmail 20 minutes. We suggest to use less than 10 minutes.
-p pidfile
Use this pid file (default /var/run/amavis/amavisd-milter.pid).
-P
When amavisd-new fails mail will be passed through unchecked.
-q backlog
Sets the incoming socket backlog used by listen(2) . If it is not set or set to zero, the operating system default is used.
-s socket
Communication socket between sendmail and (default /var/lib/amavis/amavisd-milter.sock). The protocol spoken over this socket is MILTER (Mail FILTER). It must agree with the INPUT_MAIL_FILTER entry in sendmail.mc

The socket should be in "proto:address" format:

-S socket
Communication socket between and amavisd-new (default /var/lib/amavis/amavisd.sock). The protocol spoken over this socket is AM.PDP (AMavis Policy Delegation Protocol). It must agree with the $unix_socketname entry in amavisd.conf.

The socket should be in "proto:address" format:

  • {unix|local}:/path/to/file - A named pipe.

-t timeout
sendmail connection timeout in seconds (default 600 = 10 minutes). It must agree with the INPUT_MAIL_FILTER entry in sendmail.mc and must be greater than or equal to the amavisd-new connection timeout. When you use other milters (especially time-consuming), the timeout must be sufficient to process message in all milters.
-T timeout
amavisd-new connection timeout in seconds (default 600 = 10 minutes). This timeout must be sufficient for message processing in amavisd-new . It's usually a good idea to adjust them to the same value as sendmail connection timeout.
-v
Report the version number and exit.
-w directory
Set working directory (default /var/lib/amavis/tmp).

Limited support for sendmail 8.12

  • Fn smfi_addheader is used instead of Fn smfi_insheader for insheader and addheader AM.PDP responses. This works well with amavisd-new 2.4.3 or newer.
  • Fn smfi_progress isn't called when amavisd-milter wait for amavisd-new communication socket.
  • AM.PDP response quarantine isn't implemented.

FILES

/var/run/amavis/amavisd-milter.pid
The default process-id file.
/var/lib/amavis/amavisd-milter.sock
The default sendmail communication socket.
/var/lib/amavis/amavisd.sock
Th default amavisd-new communication socket.
/var/lib/amavis/tmp
The default working directory.

POLICY BANK

When remote client is authenticated, amavisd-milter forward this information to amavisd-new through AM.PDP request attribute policy_bank :

SMTP_AUTH
Indicate that the remote client is authenticated.
SMTP_AUTH_<MECH>
Remote client authentication mechanism.
SMTP_AUTH_<MECH>_<BITS>
The number of bits used for the key of the symmetric cipher when authentication mechanism use it.

EXAMPLES

Configuring amavisd-new

In amavisd.conf file change protocol and socket settings to:
$protocol = "AM.PDP";                      # Use AM.PDP protocol
$unix_socketname = "$MYHOME/amavisd.sock"; # Listen on Unix socket
### $inet_socket_port = 10024;             # Don't listen on TCP port

Then (re)start amavisd daemon.

Configuring sendmail

To the sendmail.mc file add the following entries:
define(`confMILTER_MACROS_ENVFROM',
        confMILTER_MACROS_ENVFROM`, r, b')
INPUT_MAIL_FILTER(`amavisd-milter',
        `S=local:/var/lib/amavis/amavisd-milter.sock,
        F=T, T=S:10m;R:10m;E:10m')

Then rebuild your sendmail.cf file, install it (usually to /etc/mail/sendmail.cf) and (re)start sendmail daemon.

Running

This example assume that amavisd-new is running as user amavis . It must agree with the entry $daemon_user in amavisd.conf.

First create working directory:

mkdir /var/lib/amavis/tmp
chmod 750 /var/lib/amavis/tmp
chown amavis /var/lib/amavis/tmp

Then start as non-priviledged user amavis:

su - amavis -c " -w /var/lib/amavis/tmp

Limiting maximum concurrent connections to amavisd

To limit concurrent connections to 4 and fail after 10 minutes (10*60 secs) of waiting run with this options:

su - amavis -c " -w /var/lib/amavis/tmp -m 4 -M 600

Troubleshooting

For troubleshooting run on the foreground and set debug level to appropriate level:

su - amavis -c " -w /var/lib/amavis/tmp -f -d level

where debug levels are:

1
Not errors but unexpected states (connection abort etc).
2
Main states in message processing.
3
All debug messages.
4-9
Milter communication debugging (smfi_setdbg 1-6).

AUTHORS

This manual page was written by Petr Rehor <[email protected]> and is based on Jerzy Sakol <[email protected]> initial work.

BUGS

A community mailing lists are available at:
http://sourceforge.net/mail/?group_id=138169

Enhancements, requests and problem reports are welcome.

If you run into problems first check the users mailing list archive before asking questions on the list. It's highly likely somebody has already come across the same problem and it's been solved.