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dblist(DCC) LOCAL dblist(DCC)

NAME

dblist — Database List Distributed Checksum Clearinghouse

SYNOPSIS

dblist [−vVHD] [−G on | off] [−h homedir] [−C ’type h1 h2 h3 h4’]
[−I server-ID] [−A dbaddr] [−L pathlen] [−P pages] [−T timestamp]
[file1 file2 ...]

DESCRIPTION

Dblist lists the contents of a DCC database as it does some consistency checking.

−v

lists more of the database. Additional information is produced with additional −v arguments.

−V

displays the version of the DCC database lister.

−H

turns off the listing of the hash table as well as the analysis of the hash table. Determining the worst case and average lengths of chains in the hash table can take a long time for a large database on a small computer.

−D

turns off the listing of the data or checksum records.

−G on

lists a greylist database.

−h homedir

overrides the default DCC home directory, which is often /var/dcc.

−C ’type h1 h2 h3 h4’

limits the listing to records containing that checksum or one of the other checksums specified with −C or server-IDs specified with −I. As many as 16 checksums can be specified.

−I server-ID

limits the listing to records with that server-ID or one of the other server-IDs specified with −I or checksums specified with −C. As many as 16 server-IDs can be specified.

−A dbaddr

excludes database records before dbaddr.

−L pathlen

excludes records with path lengths shorter than pathlen.

−P pages

ignores all but the last pages of the database.

−T timetamp

excludes records with other timestamps. As many as 16 timestamps can be specified.

file1 file2 ...

are names of databases to be listed. The default is dcc_db and its companion, dcc_db.hash in the DCC home directory.

By default, the sizes of the main file and the hash table as well as how much they contain and values related to the performance of the hash are displayed.

With a single −v, most of the mail database file and the contents of memory mapped server flooding positions in the flod.map file are listed. The listing starts with the serial number of the database file which is when old entries were last removed from it by dbclean(8) That is followed by similar lines showing the oldest timestamp of checksums not expired by dbclean and of mail that is not "spam."

The flooding positions from the flod.map file are record offsets or addresses in the main database file.

A typical record in the main database file looks like:

02/07/02 20:25:12.497032 5 auth 1601 2fe5b94
path: 103<-101<-1601

Body

That example was received by a DCC server with server-ID 1601 at about 8:25 GMT on the evening of February 7, 2000. The report was about a mail message set to 5 addressees. The report was from a client that presented a client-ID and matching password that the server recognized or authenticated. The report was then sent or ’flooded’ to the server with server-ID 101 which in turn sent it to a server with server-ID 103. That server sent it to the local DCC server. The record is at the address 0x2fe5b94 in the database. The record contains 3 checksums. The simple checksum of the body of the message was e2d3f96a c65aea01 3fece361 edff9ecf The total number of recipients of messages with this body checksum known in the database is 6, which implies this checksum had been previously reported with a target count of 1. The previous report in the database of a message with this body checksum is at 0x2f21364. The hash table entry for this body checksum is at 0x772d2. This report included two fuzzy checksums. Both have been previously reported as having been sent to many targets.

An asterisk (*) before the name of the checksum would indicate that a later record in the database makes this checksum redundant. A report of many addressees makes all preceding reports redundant.

The string trimmed after the server-ID marks older reports that have had uninteresting checksums removed. The string compressed after the server-ID would indicate that this older report has been trimmed and compressed with older reports.

With two −v arguments, records added to the database by dbclean(8) from the server whitelist are also displayed.

Three −v arguments cause the hash table to be displayed. Three typical hash table entries look like:

19b8: 19ee 19b7
19b9: 19c0 0 90120 Fuz1
19ba: 0 0 1b72300 Fuz1

The entry in slot number 0x19b8 is unused or free. Slot number 0x19b9 is the start of a chain of collisions or entries with the same hash value of 0x19b9. The next slot in this chain is at 0x19c0. The corresponding Fuz1
checksum is at 0x9012 in the database. The third slot at 0x19ba is also that of a Fuz1 checksum, but it is not part of a hash chain and its database record is at 0x1b72300.

FILES
/var/dcc

is the DCC home directory containing data and control files.

dcc_db grey_dcc_db

main file of checksums.

dcc_db.hash grey_dcc_db.hash

database hash table.

flod.map grey_flod.map

memory mapped flooding positions.

SEE ALSO

cdcc(8), dcc(8), dbclean(8), dccd(8), dccifd(8), dccm(8), dccproc(8).

HISTORY

Implementation of dblist was started at Rhyolite Software in 2000. This describes version 1.2.74.

March 28, 2017