Langue: en

Version: 65998 (mandriva - 22/10/07)

Section: 8 (Commandes administrateur)

BSD mandoc


dbclean - Clean Distributed Checksum Clearinghouse Database


-words dbclean [-dDfFNRPSVq [-i id ] ] [-a [server-addr ] [,port ] ] [-h homedir ]
[-G on ] [-s hash-size ] [-e seconds ] [-E spamsecs ]
[-t type,allsecs,threshold,bulksecs ] [-L ltype,facility.level ]


Dbclean creates empty, rebuilds corrupted, and deletes or expires old reports of checksums from DCC databases. It should be installed where it will be found with the path given the DCC server daemon when the daemon needs to expand the hash table. See dccd(8). It should also be run by cron(8) approximately daily.

If the hash table in the database has been damaged, dbclean tries to repair the database.

The contents of the whitelist file are built into the DCC server's database. Changes to the whitelist are not effective until dbclean is run to expire reports. White or blacklists can also be used by DCC clients, and generally work better there.


The following options are available:
enables debugging output. Additional -d options increase the number of messages.
indicates that dccd(8) started .
uses write() instead of mmap() in some cases to modify the DCC database. This works better on some versions of Solaris provided the entire DCC database fits in RAM and provided the file system has not been tuned for the large, random accesses of a DCC database. It is the default on Solaris.
turns off -F
creates a new, empty database. There must not be an existing database and the DCC server, dccd(8), must not be running.
repairs a database.
expires old checksums from a database using the -e -E and -t values from the preceding use of dbclean -P cannot be used with -e -E or -t Note also that using -P differs from not using -e -E or -t because in the absence of all four, their default values are used.
says that the DCC server, dccd(8), is not running and so dbclean should run stand-alone and not try to tell the DCC server about changes to the database. -i is not needed when -S is present.
displays the version of the DCC database cleaner.
quiets the announcement of results at the end.
-i id
specifies the DCC ID recognized by the local DCC server as its own. This ID allows the DCC server to recognize commands from dbclean to stop using the database while it is being cleaned.
-a [server-addr ] [,port ]
is commonly used to specify a UDP port or IP address of the local server other than the default.
-h homedir
overrides the default DCC home directory, which is often /var/lib/dcc.
-G on
cleans a greylist database.
-s hash-size
specifies a size for the hash table. By default the hash table is rebuilt to be approximately 80% full based on an estimate of the number of distinct checksums in the main file.
-e seconds
specifies that reports older than seconds and with totals below their -t thresholds should be deleted. Reports older than seconds of checksums that have been reported more recently are summarized in the database. The default value is 1DAY or the value of -E whichever is smaller. The 1 day default is reduced if the system does not appear to have enough RAM to hold the database. The minimum is 1 hour. Seconds can also be NEVER or a number of hours, days, or weeks followed by HOURS H DAYS D WEEKS or W

The -e thresholds for both DCC Reputation counts must be the same. Their default values of 1DAY is not affected by the size of the system's RAM.

DCC servers that are not very busy and are isolated or do not receive "floods" of checksums from busy servers should use longer values to increase their chances of recognizing bulk mail.

-E spamsecs
changes the expiration of checksums exceding -t thresholds from the default of 30DAYS or the explicit value of -e whichever is larger. The default is reduced if the system does not have enough RAM to hold the database. Spamsecs can also be NEVER or a number of hours, days, or weeks followed by HOURS H DAYS D WEEKS or W
-t type,allsecs [,threshold,bulksecs ]
overrides the global -e setting and specifies that reports of checksums of type with total counts of at least threshold should be kept for bulksecs seconds. All reports should be kept for the shorter duration, allsecs seconds. The threshold is either a number or the string MANY indicating millions of targets. By default dbclean acts as if given -words -t Fuz1,seconds,10,spamsecs -t Fuz2,seconds,10,spamsecs where seconds is the value for -e and spamsecs is the value for -E All other checksum types act by default as if -words -t type,seconds were specified. Allsecs and bulksecs can also be NEVER or a number of hours, days, or weeks followed by HOURS H DAYS D WEEKS or W

Threshold for both DCC Reputation counts is fixed at the equivalent of 1%.

-L ltype,facility.level
specifies how messages should be logged. Ltype must be error or info to indicate which of the two types of messages are being controlled. Level must be a syslog(3) level among EMERG ALERT CRIT , ERR WARNING NOTICE INFO and DEBUG Facility must be among AUTH AUTHPRIV CRON DAEMON FTP KERN LPR MAIL NEWS USER UUCP and LOCAL0 through LOCAL7 The default is equivalent to

dbclean exits 0 on success, and > 0 if an error occurs.


is the DCC home directory containing data and control files.
is the main file containing mail checksums.
mail checksum database hash table.
is the database of greylist checksums.
is the greylist database hash table.
dcc_db-new , dcc_db-new.hash , grey_db-new , grey_db-new.hash
new database and hash files until they are renamed.
dcc_db-old , grey_db-old
previous database files.
list of IDs and passwords, as described in dccd(8).
contains the DCC server whitelist in the format described in dcc(8).
contains the greylist server whitelist.


cdcc(8), cron(8), dcc(8), dccd(8), dblist(8), dccifd(8), dccm(8), dccproc(8).


Implementation of dbclean was started at Rhyolite Software, in 2000. This describes version 1.3.48.