Configuration

Table Of Contents

• Configuration
  • clamconf
  • clamd.conf
    • On-Access Scanning
  • freshclam.conf
  • clamav-milter

clamconf

clamconf is a tool ClamAV provides for checking your entire system configuration, as it relates to your ClamAV installation. When run, it displays values used when configuring ClamAV at compilation time, important OS details, the contents (and validity) of both clamd.conf and freshclam.conf, along with other important engine, database, platform, and build information.

It can also generate example configuration files for clamd.conf and freshclam.conf.

To use clamconf, and see all the information it provides, simply run the following command:

$ clamconf

For more detailed information on clamconf, run:

$ man clamconf

or

$ clamconf --help

clamd.conf

Currently, ClamAV requires users to edit their clamd.conf.example file before they can run the daemon. At a bare minimum, users will need to comment out the line that reads “Example”, else clamd will consider the configuration invalid, ala:

    7 # Comment or remove the line below.
    8 #Example

You will also need to rename clamd.conf.example to clamd.conf via:

$ mv ./clamd.conf.example ./clamd.conf

If you are setting up a simple, local clamd instance then some other configuration options of interests to you will be as follows:

    91 # Path to a local socket file the daemon will listen on.
    92 # Default: disabled (must be specified by a user)
    93 LocalSocket /tmp/clamd.socket

    ...

    99 # Sets the permissions on the unix socket to the specified mode.
    100 # Default: disabled (socket is world accessible)
    101 LocalSocketMode 660

Beyond that, clamd.conf is well commented and configuration should be straightforward.

If needed, you can find out even more about the formatting and options available in clamd.conf with the command:

man clamd.conf

On-Access Scanning

You can configure On-Access Scanning through clamd.conf. Configuration for On-Access Scanning starts at line 613 in `clamd.conf.sample”. All options are grouped acording to use and roughly ordered by importance in those groupings. Please carefully read the explanation of each option to see if it might be of use to you.

Also read the on-access section of the Usage manual for further details on using On-Access Scanning.

freshclam.conf

freshclam is the automatic database update tool for Clam AntiVirus. It can be configured to work in two modes:

• interactive - on demand from command line
• daemon - silently in the background

freshclam is an advanced tool: it supports scripted updates (instead of transferring the whole CVD file at each update it only transfers the differences between the latest and the current database via a special script), database version checks through DNS, proxy servers (with authentication), digital signatures and various error scenarios.

Quick test: run freshclam (as superuser) with no parameters and check the output.

$ freshclam

If everything is OK you may create the log file in /var/log (ensure the directory is owned either by clamav or whichever user freshclam will be running as):

    # touch /var/log/freshclam.log
    # chmod 600 /var/log/freshclam.log
    # chown clamav /var/log/freshclam.log

Now you should edit the configuration file freshclam.conf and point the UpdateLogFile directive to the log file. Finally, to run freshclam in the daemon mode, execute:

    # freshclam -d

The other way is to use the cron daemon. You have to add the following line to the crontab of root or clamav user:

    N * * * *   /usr/local/bin/freshclam --quiet

to check for a new database every hour. N should be a number between 3 and 57 of your choice. Please don’t choose any multiple of 10, because there are already too many clients using those time slots. Proxy settings are only configurable via the configuration file and freshclam will require strict permission settings for the config file when HTTPProxyPassword is turned on.

    HTTPProxyServer myproxyserver.com
    HTTPProxyPort 1234
    HTTPProxyUsername myusername
    HTTPProxyPassword mypass

clamav-milter

ClamAV includes a mail filtering tool called clamav-milter. This tool interfaces directly with clamd, and thus requires a working clamd instance to run. However, clamav-milter’s configuration and log files are separate from that of clamd.

Ensuring ClamAV compiles with clamav-milter must be done at configure time with the command:

$ ./configure [options] --enable-milter

This requires having the milter library installed on your system. If libmilter is not installed, ./configure will exit with this error message:

    checking for mi_stop in -lmilter... no
    configure: error: Cannot find libmilter

While not necessarily complicated, setting up the clamav-milter is an involved process. Thus, we recommend consulting your MTA’s manual on how to best connect ClamAV with the clamav-milter.