The CNF file extension is used in the Telnet program that enables users to log in to UNIX computers through a text-based platform. CNF files can be edited with the appropriate software.CNF files are also used as configuration files in the Lotus 1-2-3 spreadsheet program that allow users to make alterations to the pre-set program. Lotus 1-2-3 CNF files are written in ASCII and can be edited with the appropriate software.
Configuration file used by MySQL, an open source relational database program; contains settings such as the default character encoding, timeouts, and cache and buffer settings; often modified to fine-tune performance depending on the use of the database. The MySQL configuration file has the name my.cnf. It is most often located in the /etc/ directory. The file is saved in a plain text format.