clamsmtpd(8) reads a configuration file when
starting up. The location of the file is dependent on how you compiled
clamsmtp but it should usually be in either the
/usr/local/etc/ or /etc/
directories. If clamsmtpd(8) does not find its
configuration file it'll print a warning when it starts up along with the
location it's expecting to find it in. You can also specify a different
location for a config file by passing the -f
argument to clamsmtpd(8)
The settings are specified one per line. The setting names come
first, followed by a colon and then the value. Comments start with the '#'
character on a line of their own. Whitespace is ignored at the beginning of
line, end of line and around the colons.
A sample configuration file can be found in the
doc/ directory of the clamsmtp distribution.
The various settings are as follows:
- Action
- This option controls what clamsmtpd(8) does when it
finds a virus. The options are:
- bounce
- Bounce the email. In most cases this is not a good idea since many
viruses spoof sender addresses.
- drop
- Silently drop the email. Recommended.
- pass
- Pass on the email. Inserts an 'X-Virus-Infected' header.
[ Default: drop ]
- ClamAddress
- Specifies the address to connect to clamd(8) on. See
syntax of addresses below.
[ Default: /var/run/clamav/clamd ]
- Header
- A header to add to scanned messages. Put an empty value to suppress adding
a header. You can include the following special formatting characters in
the string to include special values:
- %i
- Client IP Address
- %l
- Local IP Address
- %d
- Current Date
You can also include the standard \r or \n escapes.
[ Default: 'X-Virus-Scanned: ClamAV using ClamSMTP' ]
- KeepAlives
- On slow connections the server will sometimes timeout before
clamsmtpd(8) is finished scanning the file. This option
sends NOOP's to the server to keep the connection alive. Specify the
number of seconds, or 0 to disable.
[ Default: 0 ]
- Listen
- The address and port to listen for SMTP connections on. See syntax of
addresses below.
[ Default: port 10025 on all local IP addresses ]
- PidFile
- Specifies a location for the a process id file to be written to. This file
contains the process id of
clamsmtpd.conf and can
be used to stop the daemon. If the -p argument is
passed on the command line, then this setting will be ignored.
[ Default: none ]
- Quarantine
- Quarantine files that contain viruses by leaving them in the
TempDirectory directory. The file names look like
this (where X is a random character or number):
virus.XXXXXX
[ Default: off ]
- MaxConnections
- Specifies the maximum number of connections to accept at once.
clamd(8) also needs to be setup to accept at least this
number of connections.
[ Default: 64 ]
- OutAddress
- The address of the SMTP server to send email to once it's been scanned.
See syntax of addreses below.
[ Required ]
- TempDirectory
- The directory to write temp files to. This directory needs to be
accessible to both clamd(8) and
clamsmtpd(8)
[ Default: /tmp ]
- TimeOut
- The number of seconds to wait while reading data from network connections.
[ Default: 180 seconds ]
- TransparentProxy
- This option enables transparent proxy support, which allows you to route
all SMTP traffic that's going through a gateway through clamsmtp which
will then send it on to its final destination. This setup usually involves
firewall rules which redirect traffic to clamsmtp, and the setup varies
from OS to OS.
[ Default: off ]
- User
- The user to run as. If this option is specified then
clamsmtpd(8) must be started as root. It will then drop
root privileges and run as the specified user. The user can either be a
name or a numerical user id.
[ Optional ]
- VirusAction
- This is a command to run when a virus is found. See the VIRUS ACTION
section in clamsmtpd(8) for a discussion of this option.
[ Default: off ]
- XClient
- Send an XCLIENT command to the receiving server. This is useful for
forwarding client addresses and connection info to servers that support
this feature.
[ Default: off ]
Addresses can be specified in multiple formats:
- Unix local addresses can be specified by specifying their full path. (ie:
'/var/run/clamav/clamd').
- IP addresses can be specified using dotted notation with a colon before
the port number (ie: '127.0.0.1:3310').
- IPv6 addresses are implemented but disabled. The code needs testing.
Stef Walter
⟨stef@memberwebs.com⟩