clamav-milter.conf - Configuration file for
clamav-milter
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.
- 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)
- 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).
- 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
- 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 originated, non-smtp, email use the keyword
"local"
Default: unset (scan everything regardless of the origin)
- AllowList
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 allowed. 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 allowing 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
The following group of options controls the delivery process under
different circumstances. The following actions are available:
- Accept: The message is accepted for delivery
- Reject: Immediately refuse delivery (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
- 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 delivery.
Default: disabled
- 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
All options expressing a size are limited to max 4GB. Values in
excess will be reset to the maximum.
/etc/clamav/clamav-milter.conf