Browse Definitions :
Definition

blacklist

Contributor(s): Matthew Haughn

A blacklist, in IT, is a collection of entities that are blocked from communicating with or logging into a computer, site or network. Blocked entities are typically identified as IP addresses, user IDs, domains, email addresses, MAC addresses or programs.  Blacklisting is a common feature in antivirus programs, intrusion prevention/detection systems and spam filters. Blacklists save effort by limiting interactions with known sources of problems and preventing potential attacks.

Network administrators and users alike employ blacklists to block entities who would be likely to cause problems. The problem entities could be malware networks, spammers, hackers, DoS (denial of service) attackers or abusive site or forum users, among a plethora of other possibilities. Application blacklisting prevents the execution of undesirable programs, which include applications that are known to contain security threats or vulnerabilities and those that are deemed inappropriate for a given business environment. Hackers and IT security researchers sometimes use blacklists differently, seeking interaction with blacklisted entities to provide information.

Assembled blacklists are available for particular sources of problems, such as known malware networks or spammers. Spamhaus, for example, provides recommended block lists for IP addresses known to be associated with spam and those known to be hijacked by third-party exploits. Due to differences in online communication needs and the variety of online threats, however, blacklists work best when customized.

Whitelisting, the opposite approach, validates permitted entities and blocks communications from all other sources.

This was last updated in July 2016

Continue Reading About blacklist

Start the conversation

Send me notifications when other members comment.

Please create a username to comment.

-ADS BY GOOGLE

File Extensions and File Formats

SearchCompliance

  • regulatory compliance

    Regulatory compliance is an organization's adherence to laws, regulations, guidelines and specifications relevant to its business...

  • Whistleblower Protection Act

    The Whistleblower Protection Act of 1989 is a law that protects federal government employees in the United States from ...

  • smart contract

    A smart contract, also known as a cryptocontract, is a computer program that directly controls the transfer of digital currencies...

SearchSecurity

  • RSA algorithm (Rivest-Shamir-Adleman)

    The RSA algorithm is the basis of a cryptosystem -- a suite of cryptographic algorithms that are used for specific security ...

  • remote access

    Remote access is the ability to access a computer or a network remotely through a network connection.

  • IP Spoofing

    IP spoofing is the crafting of Internet Protocol (IP) packets with a source IP address that has been modified to impersonate ...

SearchHealthIT

SearchDisasterRecovery

  • virtual disaster recovery

    Virtual disaster recovery is a type of DR that typically involves replication and allows a user to fail over to virtualized ...

  • tabletop exercise (TTX)

    A tabletop exercise (TTX) is a disaster preparedness activity that takes participants through the process of dealing with a ...

  • risk mitigation

    Risk mitigation is a strategy to prepare for and lessen the effects of threats faced by a data center.

SearchStorage

  • enterprise storage

    Enterprise storage is a centralized repository for business information that provides common data management, protection and data...

  • disk array

    A disk array, also called a storage array, is a data storage system used for block-based storage, file-based storage or object ...

  • optical storage

    Optical storage is any storage type in which data is written and read with a laser. Typically, data is written to optical media, ...

Close