1. System & Network Administration (MCSA & RHCSA)
Lecture 1-2 By Waseem Ahmad
Topic :LINUX BOOT

2. Login Process DHCP SERVER INTRO:
IT ASSIGN IP ADDRESS TO NEWLY CONNECTED NODE IN THE NETWORK.
DHCP SCOPE:
DHCP ALSO CONFIGURE SOME OTHERS IP WITH ITSELF THAT CALLLED THE SCOPE OF THE DHCP .
DHCP SCOPE OPTION :Men whtas type of scope parameter is configure with DHCP SERVER.
Like DNS SERVER IP ADRESS, YPUR GATEWAY IP ADDRESS.
DHCP DISCOVERY:
A message of the broadcast type send by the host that need Ip Address .the DCHP assign the ip address for short time 3 hour in Lan and 8 Hour in wireless network but you can modify the time .
Reservation:
IP address to server like a web server or other type of server is not assigned by the DHCP SERVER its should be separated otherwise DNS have to updated daily .

3. After Running that it set rest of variable and set them in Profile .d
After Completing the work of Profile .d the next script is run in the user Home Dir. .bash_profile Then it also set the .bashrc ->you can Change your cmd Look and feel from Here.

4. Now Login as Root Make new user
Command:
SU For Switching the user as Root
Useradd waseem
Ls /home/
Userdel –r waseem
///////// -r mean recursive deletion if we used the all data regarding user including its home dir and mailbox also deleted.
Until you not gives the password and run user add command this user remain in active .
2- Check user home directory create or not .

5. User Important
If we want to to show complete name of the user on login
useradd –c “waseem ” ahmad
By default the user directory create in home we can change the location of directory.
Mkdir/home/admin
Useradd –c “fawad” -d /home/admin/fawad fawad
To modify the user used usermod command
Like e.g usermod –c “asim khan ” asim

6. User Important How to Expire the user passwd
Lock user account
Passwd –l user // it will lock user9
Passwd –u user9 // it will unlock user9
We Enforce User to change its passwd after some time period /
Chage –M 90 user1
Chage –W 3 user1
How to Expire the user passwd
Chage -E user1 //expire user passwd on this date

7. Location of user files /etc/ passwd /etc/shadow /etc/group
/etc/gshadow

8. Help and shutdown in Linux
MAN AND INFO
Reboot , init 6, init 0,
Shutdown -r //after 5 minute it shutdown
Shutdown –c //to cancel
Shutdown -h 22:00 “system will not available after 10 pm ”//show warning to all user