.cnf files are proprietary binary configuration files located in the ctrl directory and node directories and are maintained using the SCFG utility before Synchronet v3.20.
SCFG features an auto-backup system controlled with the SCFG -b# command-line option to specify the backup level. -b5 is the default, providing for 5 backups of each file modified. -b0 disables the auto-backup feature.
.cnf files ending with .0.cnf represent the most recent backup of the .cnf file, .1.cnf the next to most recent backup, etc.
The oldest backup files (e.g. *.5.cnf when the backup level is 5) are automatically removed (deleted).
The various .cnf files are:
chat.cnf: This contains the Chat Features settings from SCFG specifically the Guru, Multinode chat actions and channels, and external sysop pages. This is unused on most BBSs and may be removed from or integrated with the ircd in version 4.file.cnf: Contains the file library and directory configuration from File Areas and the file transfer configuration from File Optionsmsgs.cnf: Contains the message groups and sub-boards configured via Message Areas, Message Options, and Networksxtrn.cnf: Contains the External Programs configuration which includes events, external editors, hot-key events and doorsnode.cnf: Located in the NODE Directories, and configured via the Nodes menu, it is expected that only the node config which corresponds to the FirstNode value (usually 1) in sbbs.ini is actually used, but there may be times with some tools that a different node config file is used. Because of this, it is recommended that a sysop ensure that all node.cnf files for the same instance are configured identically.
These files were originally a text-based configuration (*.cfg files in Synchronet version 1) but were converted to binary for efficiency reasons that no longer apply. In version 3.20 of Synchronet, these files were converted to .ini files; see newcfgfiles for details.