NAME¶
clamav-milter.conf - Configuration file for clamav-milter
DESCRIPTION¶
clamav-milter.conf contains the configuration options for
clamav-milter(8).
The file consists of comments and options with arguments. Each line which starts
with a hash (
#) symbol is ignored by the parser. Options and arguments
are case sensitive and of the form
Option Argument. The arguments are
of the following types:
- BOOL
- Boolean value (yes/no or true/false or 1/0).
- STRING
- String without blank characters.
- SIZE
- Size in bytes. You can use 'M' or 'm' modifiers for
megabytes and 'K' or 'k' for kilobytes.
- NUMBER
- Unsigned integer.
MAIN OPTIONS¶
- Example
- If this option is set clamav-milter will not run.
- MilterSocket STRING
- Define the interface through which we communicate with
sendmail. This option is mandatory!
Possible formats are:
[[unix|local]:]/path/to/file - to specify a unix domain socket
inet:port@[hostname|ip-address] - to specify an ipv4 socket
inet6:port@[hostname|ip-address] - to specify an ipv6 socket
Default: unset
- MilterSocketGroup STRING
- Define the group ownership for the (unix) milter socket.
Default: disabled (the primary group of the user running clamd)
- MilterSocketMode STRING
- Sets the permissions on the (unix) milter socket to the
specified mode.
Default: disabled (obey umask)
- FixStaleSocket BOOL
- Remove stale socket after unclean shutdown.
Default: yes
- User STRING
- Run as another user (clamav-milter must be started by root
for this option to work)
Default: unset (don´t drop privileges)
- AllowSupplementaryGroups BOOL
- Initialize supplementary group access (clamav-milter must
be started by root).
Default: no
- ReadTimeout NUMBER
- Waiting for data from clamd will timeout after this time
(seconds).
Default: 120
- Foreground BOOL
- Don´t fork into background.
Default: no
- Chroot STRING
- Chroot to the specified directory. Chrooting is performed
just after reading the config file and before dropping privileges.
Default: unset (don´t chroot)
- PidFile STRING
- Save the process identifier of a clamav-milter (main
thread) to a specified file.
Default: disabled
- TemporaryDirectory STRING
- Optional path to the global temporary directory.
Default: system specific (usually /tmp or /var/tmp).
CLAMD OPTIONS¶
- ClamdSocket STRING
- Define the clamd socket to connect to for scanning. This
option is mandatory! Syntax:
ClamdSocket unix:path
ClamdSocket tcp:host:port
The first syntax specifies a local unix socket (needs an absolute path)
e.g.:
ClamdSocket unix:/var/run/clamd/clamd.socket
The second syntax specifies a tcp local or remote tcp socket: the host can
be a hostname or an ip address; the ":port" field is only
required for IPv6 addresses, otherwise it defaults to 3310 e.g.:
ClamdSocket tcp:192.168.0.1
This option can be repeated several times with different sockets or even
with the same socket: clamd servers will be selected in a round-robin
fashion.
Default: no default
EXCLUSIONS¶
- LocalNet STRING
- Messages originating from these hosts/networks will not be
scanned. This option takes a host(name)/mask pair in CIRD notation and can
be repeated several times. If "/mask" is omitted, a host is
assumed. To specify a locally orignated, non-smtp, email use the keyword
"local"
Default: unset (scan everything regardless of the origin)
- Whitelist STRING
- This option specifies a file which contains a list of basic
POSIX regular expressions. Addresses (sent to or from - see below)
matching these regexes will not be scanned. Optionally each line can start
with the string "From:" or "To:" (note: no whitespace
after the colon) indicating if it is, respectively, the sender or
recipient that is to be whitelisted. If the field is missing,
"To:" is assumed. Lines starting with #, : or ! are ignored.
Default: unset (no exclusion applied)
- SkipAuthenticated STRING
- Messages from authenticated SMTP users matching this
extended POSIX regular expression (egrep-like) will not be scanned. As an
alternative, a file containing a plain (not regex) list of names (one per
line) can be specified using the prefix "file:". e.g.
SkipAuthenticated file:/etc/good_guys. Note: this is the AUTH login name!
Default: unset (no whitelisting based on SMTP auth)
- MaxFileSize SIZE
- Messages larger than this value won´t be scanned. Make
sure this value is lower or equal than StreamMaxLength in clamd.conf
Default: 25M
ACTIONS¶
The following group of options controls the delievery process under different
circumstances. The following actions are available:
- Accept: The message is accepted for delievery
- Reject: Immediately refuse delievery (a 5xx error is returned to the peer)
- Defer: Return a temporary failure message (4xx) to the peer
- Blackhole (not available for OnFail): Like Accept but the message is sent to
oblivion
- Quarantine (not available for OnFail): Like Accept but message is quarantined
instead of being delivered. NOTE: In Sendmail the quarantine queue can be
examined via mailq -qQ. For Postfix this causes the message to be placed on
hold.
- OnClean STRING
- Action to be performed on clean messages (mostly useful for
testing)
Default: Accept
- OnInfected STRING
- Action to be performed on infected messages
Default: Quarantine
- OnFail STRING
- Action to be performed on error conditions (this includes
failure to allocate data structures, no scanners available, network
timeouts, unknown scanner replies and the like)
Default: Defer
- RejectMsg STRING
- This option allows you to set a specific rejection reason
for infected messages and it´s therefore only useful together with
"OnInfected Reject". The string "%v", if present, will
be replaced with the virus name.
Default: MTA specific
- AddHeader STRING
- If this option is set to "Replace" (or
"Yes"), an "X-Virus-Scanned" and an
"X-Virus-Status" headers will be attached to each processed
message, possibly replacing existing headers. If it is set to Add, the
X-Virus headers are added possibly on top of the existing ones. Note that
while "Replace" can potentially break DKIM signatures,
"Add" may confuse procmail and similar filters.
Default: no
- ReportHostname STRING
- When AddHeader is in use, this option allows you to set the
reported hostname. This may be desirable in order to avoid leaking
internal names. If unset the real machine name is used.
Default: disabled
- VirusAction STRING
- Execute a command (possibly searching PATH) when an
infected message is found. The following parameters are passed to the
invoked program in this order: virus name, queue id, sender, destination,
subject, message id, message date. Note #1: this requires MTA macroes to
be available (see LogInfected below). Note #2: the process is invoked in
the context of clamav-milter. Note #3: clamav-milter will wait for the
process to exit. Be quick or fork to avoid unnecessary delays in email
delievery.
Default: disabled
LOGGING OPTIONS¶
- LogFile STRING
- Enable logging to selected file.
Default: no
- LogFileUnlock BOOL
- Disable a system lock that protects against running clamd
with the same configuration file multiple times.
Default: no
- LogFileMaxSize SIZE
- Limit the size of the log file. The logger will be
automatically disabled if the file is greater than SIZE. Value of 0
disables the limit.
Default: 1M
- LogTime BOOL
- Log time for each message.
Default: no
- LogSyslog BOOL
- Use system logger (can work together with LogFile).
Default: no
- LogFacility STRING
- Specify the type of syslog messages - please refer to 'man
syslog' for facility names.
Default: LOG_LOCAL6
- LogVerbose BOOL
- Enable verbose logging.
Default: no
- LogInfected STRING
- This option allows you to tune what is logged when a
message is infected. Possible values are Off (the default - nothing is
logged), Basic (minimal info logged), Full (verbose info logged)
Note: For this to work properly in sendmail, make sure the msg_id,
mail_addr, rcpt_addr and i macroes are available in eom. In other words
add a line like: Milter.macros.eom={msg_id}, {mail_addr}, {rcpt_addr}, i
to your .cf file. Alternatively use the macro:
define(`confMILTER_MACROS_EOM', `{msg_id}, {mail_addr}, {rcpt_addr}, i')
Postfix should be working fine with the default settings.
Default: disabled
- LogClean STRING
- This option allows you to tune what is logged when no
threat is found in a scanned message.
See LogInfected for possible values and caveats.
Useful in debugging but drastically increases the log size.
Default: disabled
- SupportMultipleRecipients BOOL
- This option affects the behaviour of LogInfected, LogClean
and VirusAction when a message with multiple recipients is scanned:
If SupportMultipleRecipients is off (the default) then one single log entry
is generated for the message and, in case the message is determined to be
malicious, the command indicated by VirusAction is executed just once. In
both cases only the last recipient is reported.
If SupportMultipleRecipients is on then one line is logged for each
recipient and the command indicated by VirusAction is also executed once
for each recipient.
Note: although it's probably a good idea to enable this option, the default
value is currently set to off for legacy reasons.
Default: no
NOTES¶
All options expressing a size are limited to max 4GB. Values in excess will be
resetted to the maximum.
FILES¶
/etc/clamav/clamav-milter.conf
AUTHOR¶
aCaB <acab@clamav.net>
SEE ALSO¶
clamav-milter(8),
clamd(8),
clamd.conf(5)
