Important Configuration Files

User accounts, authentication and messages

/etc/passwd Local authentication user file

/etc/shadow Local authentication password file

/etc/group Local system groups

/etc/gshadow Local system group authentication password file

/etc/sudoers Config file for SUDO

/etc/issue Text shown before a user logs in

/etc/motd Message of the day shown after a user logs in

/etc/pam.d/ Config files for PAM system authentication

/etc/profile System wide environment

/etc/profile.d/ System wide environment additional files

/etc/bashrc System wide aliases and functions

~./bash_profile User specific environment and startup programs

~/.bashrc User specific aliases and functions

Disks, scheduled tasks and other

/etc/fstab Filesystem table that lists all filesystems to be mounted

/etc/exports Exported filesystems for NFS

/etc/nsswitch.conf Determines name resolution order

/etc/hosts Static name resolution

resolv.conf External DNS servers

/etc/crontab System wide scheduled tasks

/etc/cron.d/ System wide scheduled tasks additional files

/etc/anacrontab System wide anacron scheduled tasks

/etc/cron.allow, /etc/cron.deny Allow/Deny access control for cron jobs

/etc/hosts.allow, /etc/hosts.deny Allow/deny files for ssh (and other tcpwrappers tools)

/etc/ssh/ Config files and keys for ssh

/etc/sysconfig/ System hardware config files