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In [[computing]], a '''blacklist''' is a basic [[access control]] mechanism that allows everyone access, except for the members of the ''black'' list (i.e. list of denied accesses). The opposite is a [[whitelist]], which means ''allow nobody, except members of the white list''. As a sort of middle ground, a [[Greylisting|greylist]], contains entries that are temporarily blocked or temporarily allowed. Greylist items may be reviewed or further tested for inclusion in a blacklist or whitelist.
In [[computing]], a '''blacklist''' or '''block list''' is a basic [[access control]] mechanism that allows everyone access, except for the members of the ''black'' list (i.e. list of denied accesses). The opposite is a [[whitelist]], which means ''allow nobody, except members of the white list''. As a sort of middle ground, a [[Greylisting|greylist]], contains entries that are temporarily blocked or temporarily allowed. Greylist items may be reviewed or further tested for inclusion in a blacklist or whitelist.


An organization may keep a blacklist of software or websites in its computer system. Titles on the list would be banned and everything else would be allowed. For example, a school might blacklist [[KaZaA]] and [[ICQ]]; other Internet services would still be allowed.
An organization may keep a blacklist of software or websites in its computer system. Titles on the list would be banned and everything else would be allowed. For example, a school might blacklist [[KaZaA]] and [[ICQ]]; other Internet services would still be allowed.

Revision as of 23:00, 18 December 2009

In computing, a blacklist or block list is a basic access control mechanism that allows everyone access, except for the members of the black list (i.e. list of denied accesses). The opposite is a whitelist, which means allow nobody, except members of the white list. As a sort of middle ground, a greylist, contains entries that are temporarily blocked or temporarily allowed. Greylist items may be reviewed or further tested for inclusion in a blacklist or whitelist.

An organization may keep a blacklist of software or websites in its computer system. Titles on the list would be banned and everything else would be allowed. For example, a school might blacklist KaZaA and ICQ; other Internet services would still be allowed.

Examples

  • An e-mail spam filter may keep a blacklist of addresses, any mail from which would be prevented from reaching its intended destination. A popular technique for implementing blacklists is DNS blacklisting (DNSBL).
  • Members of online auction sites may add other members to a personal blacklist. This means that they cannot bid on or ask questions about your auctions, nor can they use a "buy it now" function on your items.
  • Yet another form of list is the yellow list which is a list of email server IP addresses that send mostly good email but do send some spam. Examples include Yahoo, Hotmail, and Gmail. A yellow listed server is a server that should never be accidentally blacklisted. The yellow list is checked first and if listed then black list tests are ignored.
  • In Linux modprobe, the blacklist modulename entry in a modprobe configuration file indicates that all of the particular module's internal aliases are to be ignored. There are cases where two or more modules both support the same devices, or a module invalidly claims to support a device.

See also