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Man Pages

Manual Reference Pages  -  DBLIST (8)


dblist - Database List Distributed Checksum Clearinghouse


See Also


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


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. Two or more -V options show the options with which it was built.
-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, /usr/local/dcc.
-s -Xo
.Sm off [server-ID] [,server-addr] [,server-port]
.Sm on
  somewhat quiets the DCC server process, dccd(8), to get somewhat more consistent results. server-ID must be in the /usr/local/dcc/ids file. server-addr and server-port are the IP address and UDP port at which the server process listens.
-C ’type h1 h2 h3 h4’
  limits the listing to records containing that checksum or one of the other checksums specified with -C . If the four hexadecimal values h1 h2 h3 h4 are absent, records with the matching type will be listed. If type is absent, any checksum with the four hexadecimal values will be listed. If the hexadecimal values h1 h2 h3 h4 are absent, all checksums of the specified type will be listed.

The alternate form
.Bk -words ’server-ID {simple|commercial|ignore|rogue} at ID’
.Ek can be used to select server-ID records of some types.

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 . 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. A timestamp with a missing microsecond value matches any record with that second. As many as 16 timestamps can be specified.
file1 file2 ...
  are names of databases to be listed. The default is /usr/local/dcc/dcc_db and its companion, /usr/local/dcc/dcc_db.hash. When -G on is used, the default files are /usr/local/dcc/grey_db and /usr/local/dcc/grey_db.hash.

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 /usr/local/dcc/ 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 /usr/local/dcc/ 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         1601              2fe5b94
     path: 103<-101<-1601
  Body      6       e2d3f96a c65aea01 3fece361 edff9ecf  2f21364 772d2
  Fuz1      many    6ff56fe8 ffc312d7 a5fe8f13 12a537ae  2f21364 200a9
  Fuz2      many    fac882b8 03eea34f bd792c40 2fe6fd54  2f21364 72816

That example was received by a DCC server with server-ID 1601 at about 8:25 UTC on the evening of February 7, 2000. The report was about a mail message set to 5 addressees. 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 0xe2d3f96a 0xc65aea01 0x3fece361 0xedff9ecf 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 chain for this body checksum is computed to start at 0x772d2. This report included two fuzzy checksums. Both have been previously reported as having been sent to many targets.

An asterisk (*) before the type of the checksum indicates that this checksum is redundant. A report of many addressees makes all preceding reports redundant.

The flooding of some database records is delayed, as shown by the string delayed after the server-ID.

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.


  is the DCC home directory containing data and control files.
dcc_db main file of DCC checksums.
  main file of checksums used for greylisting.
  database hash table for /usr/local/dcc/dcc_db.
  database hash table for /usr/local/dcc/grey_dcc.
  memory mapped flooding positions.


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


Implementation of dblist was started at Rhyolite Software, in 2000. This document describes version 1.3.158.
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