clamd.conf - Configuration file for Clam AntiVirus Daemon


clamd.conf configures the Clam AntiVirus daemon, clamd(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.


When some option is not used (commented out or not included in the configuration file at all) clamd takes a default action.
 If this option is set clamd will not run.
 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
LogClean BOOL
 Log clean files. 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
ExtendedDetectionInfo BOOL
 Log additional information about the infected file, such as its size and hash, together with the virus name. Default: no
 Save the process identifier of a listening daemon (main thread) to a specified file. Default: no
TemporaryDirectory STRING
 Optional path to the global temporary directory. Default: system specific (usually /tmp or /var/tmp).
DatabaseDirectory STRING
 Path to a directory containing database files.
OfficialDatabaseOnly BOOL
 Only load the official signatures published by the ClamAV project. Default: no
LocalSocket STRING
 Path to a local (Unix) socket the daemon will listen on. Default: no
LocalSocketGroup STRING
 Sets the group ownership on the unix socket. Default: the primary group of the user running clamd
LocalSocketMode STRING
 Sets the permissions on the unix socket to the specified mode. Default: socket is world readable and writable
FixStaleSocket BOOL
 Remove stale socket after unclean shutdown. Default: yes
 TCP port number the daemon will listen on. Default: no
 TCP socket address to bind to. By default clamd binds to INADDR_ANY. Default: no
MaxConnectionQueueLength NUMBER
 Maximum length the queue of pending connections may grow to. Default: 15
MaxThreads NUMBER
 Maximum number of threads running at the same time. Default: 10
ReadTimeout NUMBER
 Waiting for data from a client socket will timeout after this time (seconds). Default: 120
CommandReadTimeout NUMBER
 This option specifies the time (in seconds) after which clamd should timeout if a client doesn’t provide any initial command after connecting. Note: the timeout for subsequents commands, and/or data chunks is specified by ReadTimeout. Default: 5
SendBufTimeout NUMBER
 This option specifies how long to wait (in milliseconds) if the send buffer is full. Keep this value low to prevent clamd hanging. Default: 500
 Maximum number of queued items (including those being processed by MaxThreads threads). It is recommended to have this value at least twice MaxThreads if possible. WARNING: you shouldn’t increase this too much to avoid running out of file descriptors, the following condition should hold: MaxThreads*MaxRecursion + MaxQueue - MaxThreads + 6 < RLIMIT_NOFILE. RLIMIT_NOFILE is the maximum number of open file descriptors (usually 1024), set by ulimit -n. Default: 100
IdleTimeout NUMBER
 Waiting for a new job will timeout after this time (seconds). Default: 30
ExcludePath REGEX
 Don’t scan files and directories matching REGEX. This directive can be used multiple times. Default: scan all
MaxDirectoryRecursion NUMBER
 Maximum depth directories are scanned at. Default: 15
FollowDirectorySymlinks BOOL
 Follow directory symlinks. Default: no
CrossFilesystems BOOL
 Scan files and directories on other filesystems. Default: yes
FollowFileSymlinks BOOL
 Follow regular file symlinks. Default: no
SelfCheck NUMBER
 Perform a database check. Default: 1800
VirusEvent COMMAND
 Execute COMMAND when a virus is found. In the command string %v will be replaced with the virus name. Default: no
 Stop daemon when libclamav reports out of memory condition. Default: no
 Run as another user (clamd must be started by root to make this option working). Default: no
AllowSupplementaryGroups BOOL
 Initialize supplementary group access (clamd must be started by root). Default: no
Foreground BOOL
 Don’t fork into background. Default: no
Debug BOOL
 Enable debug messages from libclamav.
LeaveTemporaryFiles BOOL
 Do not remove temporary files (for debug purpose). Default: no
StreamMaxLength SIZE
 Clamd uses FTP-like protocol to receive data from remote clients. If you are using clamav-milter to balance load between remote clamd daemons on firewall servers you may need to tune the Stream* options. This option allows you to specify the upper limit for data size that will be transfered to remote daemon when scanning a single file. It should match your MTA’s limit for a maximum attachment size. Default: 10M
StreamMinPort NUMBER
 Limit data port range. Default: 1024
StreamMaxPort NUMBER
 Limit data port range. Default: 2048
Bytecode BOOL
 With this option enabled ClamAV will load bytecode from the database. It is highly recommended you keep this option turned on, otherwise you may miss detections for many new viruses. Default: yes
BytecodeSecurity STRING
 Set bytecode security level. Possible values: None: no security at all, meant for debugging. DO NOT USE THIS ON PRODUCTION SYSTEMS, TrustSigned: trust bytecode loaded from signed .c[lv]d files and insert runtime safety checks for bytecode loaded from other sources, Paranoid: don’t trust any bytecode, insert runtime checks for all. The recommended setting is TrustSigned, because bytecode in .cvd files already has safety checks inserted into it. Default: TrustSigned
BytecodeTimeout NUMBER
 Set bytecode timeout in milliseconds. Default: 60000
 Detect Possibly Unwanted Applications. Default: No
 Exclude a specific PUA category. This directive can be used multiple times. See for the complete list of PUA categories. Default: Load all categories (if DetectPUA is activated)
 Only include a specific PUA category. This directive can be used multiple times. See for the complete list of PUA categories. Default: Load all categories (if DetectPUA is activated)
AlgorithmicDetection BOOL
 In some cases (eg. complex malware, exploits in graphic files, and others), ClamAV uses special algorithms to provide accurate detection. This option controls the algorithmic detection. Default: yes
 PE stands for Portable Executable - it’s an executable file format used in all 32 and 64-bit versions of Windows operating systems. This option allows ClamAV to perform a deeper analysis of executable files and it’s also required for decompression of popular executable packers such as UPX. Default: yes
 Executable and Linking Format is a standard format for UN*X executables. This option allows you to control the scanning of ELF files. Default: yes
DetectBrokenExecutables BOOL
 With this option clamd will try to detect broken executables (both PE and ELF) and mark them as Broken.Executable. Default: no
 This option enables scanning of OLE2 files, such as Microsoft Office documents and .msi files. Default: yes
OLE2BlockMacros BOOL
 With this option enabled OLE2 files with VBA macros, which were not detected by signatures will be marked as "Heuristics.OLE2.ContainsMacros". Default: no
 This option enables scanning within PDF files. Default: yes
 Enables HTML detection and normalisation. Default: yes
ScanMail BOOL
 Enable scanning of mail files. Default: yes
ScanPartialMessages BOOL
 Scan RFC1341 messages split over many emails. You will need to periodically clean up $TemporaryDirectory/clamav-partial directory. WARNING: This option may open your system to a DoS attack. Never use it on loaded servers. Default: no
MailMaxRecursion NUMBER (OBSOLETE)
 WARNING: This option is no longer accepted. See MaxRecursion.
PhishingSignatures BOOL
 With this option enabled ClamAV will try to detect phishing attempts by using signatures. Default: yes
PhishingScanURLs BOOL
 Scan URLs found in mails for phishing attempts using heuristics. This will classify "Possibly Unwanted" phishing emails as Phishing.Heuristics.Email.* Default: yes
PhishingAlwaysBlockSSLMismatch BOOL
 Always block SSL mismatches in URLs, even if the URL isn’t in the database. This can lead to false positives. Default: no
PhishingAlwaysBlockCloak BOOL
 Always block cloaked URLs, even if URL isn’t in database. This can lead to false positives. Default: no
HeuristicScanPrecedence BOOL
 Allow heuristic match to take precedence. When enabled, if a heuristic scan (such as phishingScan) detects a possible virus/phishing it will stop scanning immediately. Recommended, saves CPU scan-time. When disabled, virus/phishing detected by heuristic scans will be reported only at the end of a scan. If an archive contains both a heuristically detected virus/phishing, and a real malware, the real malware will be reported. Keep this disabled if you intend to handle "*.Heuristics.*" viruses differently from "real" malware. If a non-heuristically-detected virus (signature-based) is found first, the scan is interrupted immediately, regardless of this config option. Default: no
StructuredDataDetection BOOL
 Enable the DLP module. Default: no
StructuredMinCreditCardCount NUMBER
 This option sets the lowest number of Credit Card numbers found in a file to generate a detect. Default: 3
StructuredMinSSNCount NUMBER
 This option sets the lowest number of Social Security Numbers found in a file to generate a detect. Default: 3
StructuredSSNFormatNormal BOOL
 With this option enabled the DLP module will search for valid SSNs formatted as xxx-yy-zzzz. Default: Yes
StructuredSSNFormatStripped BOOL
 With this option enabled the DLP module will search for valid SSNs formatted as xxxyyzzzz. Default: No
ScanArchive BOOL
 Enable archive scanning. Default: yes
ArchiveMaxFileSize (OBSOLETE)
 WARNING: This option is no longer accepted. See MaxFileSize and MaxScanSize.
ArchiveMaxRecursion (OBSOLETE)
 WARNING: This option is no longer accepted. See MaxRecursion.
ArchiveMaxFiles (OBSOLETE)
 WARNING: This option is no longer accepted. See MaxFiles.
ArchiveMaxCompressionRatio (OBSOLETE)
 WARNING: This option is no longer accepted.
ArchiveBlockMax (OBSOLETE)
 WARNING: This option is no longer accepted.
ArchiveLimitMemoryUsage (OBSOLETE)
 WARNING: This option is no longer accepted. Default: no
ArchiveBlockEncrypted BOOL
 Mark encrypted archives as viruses (Encrypted.Zip, Encrypted.RAR). Default: no
MaxScanSize SIZE
 Sets the maximum amount of data to be scanned for each input file. Archives and other containers are recursively extracted and scanned up to this value. Warning: disabling this limit or setting it too high may result in severe damage to the system. Default: 100M
MaxFileSize SIZE
 Files larger than this limit won’t be scanned. Affects the input file itself as well as files contained inside it (when the input file is an archive, a document or some other kind of container). Warning: disabling this limit or setting it too high may result in severe damage to the system. Default: 25M
MaxRecursion NUMBER
 Nested archives are scanned recursively, e.g. if a Zip archive contains a RAR file, all files within it will also be scanned. This options specifies how deeply the process should be continued. Warning: setting this limit too high may result in severe damage to the system. Default: 16
 Number of files to be scanned within an archive, a document, or any other kind of container. Warning: disabling this limit or setting it too high may result in severe damage to the system. Default: 10000
ClamukoScanOnAccess BOOL
 Enable Clamuko. Dazuko (/dev/dazuko) must be configured and running. Default: no
ClamukoScannerCount NUMBER
 The number of scanner threads that will be started (DazukoFS only). Having multiple scanner threads allows Clamuko to serve multiple processes simultaneously. This is particularly beneficial on SMP machines. Default: 3
ClamukoScanOnOpen BOOL
 Scan files on open. Default: no
ClamukoScanOnClose BOOL
 Scan files on close. Default: no.
ClamukoScanOnExec BOOL
 Scan files on execute. Default: no
ClamukoIncludePath STRING
 Set the include paths (all files and directories inside them will be scanned). You can have multiple ClamukoIncludePath directives but each directory must be added in a separate line). Default: no
ClamukoExcludePath STRING
 Set the exclude paths. All subdirectories will also be excluded. Default: no
ClamukoMaxFileSize SIZE
 Ignore files larger than SIZE. Default: 5M


All options expressing a size are limited to max 4GB. Values in excess will be resetted to the maximum.




Tomasz Kojm <>


clamd(8), clamdscan(1), clamav-milter(8), freshclam(1), freshclam.conf(5)

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