Fundamentals of Linux

Fundamentals of Linux

Installing and Implementing Linux
Maintaining and Supporting Linux
Passwords
- Early versions of UNIX kept encrypted passwords in /etc/passwd file
- Most versions now keep passwords in shadow file (only accessible to root)
- UNIX uses one-way hash algorithm (Crypt)
- Some newer versions using MD5
- Encrypted password is 11 characters with a 2-character salt
Unix Commands
Access Control is managed through file permissions (rwx for owner, group, and everyone)
inetd - Internet standard services daemon; /etc/inetd.conf is the main configuration file that lists all of the services and which are active; has now been replaced by xinetd folder
netstat - program which provides information about the network on which the host is running
su and suid - su (super-user / switch user) is the root or administrative account; A program with suid permissions runs as root without the user have root privileges (ex. /usr/bin/passwd)