Blacklists may be extremely specific against particular individuals, or software programs for example.
Alternatively, they can also be quite general such as with a location-based blacklist.
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Examples of general use
A classic class of a blacklist is a list of blocked URLs.
There are plenty of potential reasons to block websites.
Common classes of sites that get blocked include sites that serve malware.
Phishing sites, gambling sites, adult content, and social media are all common targets of blacklists.
Very closely related to URL blacklists are IP blacklists.
These are more typically implemented on servers against malicious users.
It may, however, be a permanent block.
To prevent users from selecting known weak passwords, some organisations and sites implement a password blacklist.
Technically, password complexity rules dont qualify as a blacklist as they are more of a validation rule.
Nevertheless, some sites check new passwords against lists of passwords that have previously been involved in data breaches.
Some governments or organisations may implement regional blacklists.
For example, blocking access to their services to users in an authoritarian country with a repressive regime.
Conversely, authoritarian countries with repressive regimes may blacklist access to external content.
This often targets external news sources, social media platforms, or the wider Internet in general.
Methods of bypassing blacklists
It may not be possible to bypass all blacklists.
This is especially the case when dealing with systems primarily controlled by a third party.
VPNs are a classic way of bypassing blacklists.
They involve setting up an encrypted connection to a third party and then routing all traffic through there.
Some blacklists are implemented by using a custom DNS server.
IP blacklists can often be dodged by power cycling your router.
This typically results in your ISP providing you with a new public IP address to use that is unblocked.
This can negatively affect other innocent users if they later get assigned the blacklisted IP.
This is why IP-based blacklisting is typically temporary.
Attitudes on the subject tend to vary by culture and by the punch in of content blocked.
Suggested alternatives to the term blacklist include deny-list and block-list.
Whitelist primarily sees the alternative term allow-list.
While some may not agree with the suggested reasoning for the change in terminology, there are benefits.
Firstly, it does address any potential racial issues, increasing inclusivity.
Additionally, it also makes the language clearer to understand.
Most of the suggested alternative terms are instantly understandable to people for whom English is not their first language.
Some of the older terms can require a deeper cultural understanding and context rather than simply knowing the language.
The curator of the list may or may not have some sort of appeals process.
Blacklists are often used to deny access to content deemed objectionable.
They may also be used to prevent access from senders deemed objectionable.
Blacklists can be implemented at many levels, by many different curators, and are complementary.
By design an entity on the blacklist is blocked, implying all other unspecified entities are allowed.
The opposite is a whitelist.
The term blacklist is challenged for its potentially racially insensitive connotations.
The alternative terms block-list and deny-list are intended as objectionable drop-in replacement terms.
