A blacklist, a blocklist or a deny list is a list of items, such as phone numbers, email addresses, or IP addresses, that are blocked or denied access to a certain resource or service. The purpose of a blacklist is to prevent unwanted or malicious access or activity.
In mobile devices, a blacklist can block incoming calls or text messages from specific phone numbers or block certain email addresses from sending messages to a device. This can be useful for blocking spam or unwanted calls or messages. Some mobile operating systems, such as iOS and Android, include built-in call and message-blocking features that allow users to create blacklists of phone numbers.
In addition to phone calls and text messages, blacklists can be used in other areas, such as email, websites, and networks. For example, an email service provider may use a blacklist of email addresses to prevent messages from known spam sources from reaching users’ inboxes. Similarly, a network administrator may use a blacklist of IP addresses to block access to known malicious websites or to prevent certain devices from connecting to the network.
Blacklists can also be used in mobile apps, for example, a chat app can use a blacklist to prevent certain users from sending messages to other users, or a social media app can use a blacklist to prevent certain users from following or interacting with other users.
Also, See: Notification Badges