Linux O_o
By Mohamed ahmed abo-elfetoh Aka 'aboelfetouh'
Build and admin guy # !
Agenda: Linux history.
GPL.
Linux Structure.
How it works.
Build an admin !
Job seekers.
Linux History
Video !
Open source Philosophy and GPL
Copy software.
Get source code.
Distribute the altered source and binaries.
- The aim of the GPL is to keep software free , so everyone can
adapt its own needs.
Linux on !
2- Bios : a small program in EEPROM(Electrical Erasable
Programmable Read Only Memory).
Bios function
check memory check for the availabiltity aboot devices loads
Master Boot Record (MBR) of the first availale boot device .
MBR (master boot record) : its size 512 bytes
1- power on .
3- Boot Loader : after loades MBR , boot loader make its
function .
function : check partition table and looks for a partition that
is marked active.
Examples of boot loader grub and lilo ,the most common now is
grub (grand unified boot loader). Boot loader stored in MBR.
4- kernal : When the user selects a Linux operating system in
the boot loader, then the boot loader will
load the Linux kernel.
Kernal function :
it detects all hardware . switches the cpu to multitasking and
multiuser mode.
For more informations about kernal back to this topic linux
kernal .
5- Init : started by the kernal , it decide runlevel mode .
runlevels
0: halt 1: single user mode 2: multiuser without NFS 3: full
multiuser mode 4: unused 5: multiuser with graphical login 6:
reboot
Be admin guy !
- Roll the Dice
my search for "Linux Admin" on Dice.com turned up 595 job
listings. Required qualifications in the job.
Experience
Web server administration
Virtualization and managing virtual machines
Enterprise monitoring and management frameworks
Working in structured change management processes for highly
available enterprise systems
VMware
Perl, Bash, Python scripting
Work well with others
Self motivated
Ability to learn new technologies on own
Knowledge of the Linux kernel and kernel modules
IT security
Familiarity with open source tools, monitoring systems, hardware
troubleshoot, tracking, resolution, and routine maintenance with
security updates
Perform installations/patching of operating system, software
installation, and system backups - data recovery
Possess great people skills
Strong technical aptitude and ability to research and solve
complex issues independently
Systems administration vendor certification
Working exposure to networked storage (SAN, NAS) concepts
ITIL Foundation certification
Symantec
Solaris 10 experience
Red Hat clusters
RHCE certification
Do list
- Must know about :Unix
Scripting
Network
Communication
Development
Security
Design
Shell
Engineering
Do ListPlaying & Eating :)
Don't ListInstalling applications from various types- So what
happens when package A (that you installed from source) depends
upon package B (that was installed from a .deb binary) and package
B is upgraded from the update manager?
Neglecting updates- new updates can patch new exploits. Keeping
up with your updates can make the difference between a compromised
system and a secure one
Poor root password choice- The root password is the key to the
kingdom.- So why would you make the key to the kingdom simple to
crack?
Avoiding the command line- But there are times when the command
line is easier, faster, more secure
Not keeping a working kernel installed- you dont need 12 kernels
installed on one machine ! . But you do need to update your
kernel
Not understanding permissions- Permissions can make your life
really easy- 'rwx' method
Logging in as root user- Do NOT log in as root- when you log on
as a standard user, all running X applications still have access
only to the system limited to that user. If you log in as root, X
has all root permissions.- Problems :if you make a big mistake via
a GUI, that mistake can be catastrophic to the system .
with X running as root that makes your system more
vulnerable.
Don' List
Ignoring log files- /var/log , Possible security issue?-
/var/log/messageshis log file is the common log file where all
generic errors and such are logged to.
In this file you will get messages about networking, media
changes, etc.
Don't List
Thank You !
:)
Twitter : aboelfetouh_Gmail : [email protected]
