LINUX-15 BONDING/NIC TEAMING IN RHEL-6

LINUX-15 BONDING/NIC TEAMING IN RHEL-6

[root@localhost ~]# cd /etc/sysconfig/network-scripts/

[root@localhost network-scripts]# cp ifcfg-Auto_eth1 org.ifcfg-Auto_eth1

[root@localhost network-scripts]# cp ifcfg-Auto_eth2 org.ifcfg-Auto_eth2

[root@localhost network-scripts]# cp ifcfg-Auto_eth3 org.ifcfg-Auto_eth3

[root@localhost network-scripts]# cp ifcfg-eth0 org.ifcfg-eth0

LINUX-14 JOB SCHEDULING (ANACRON)

LINUX-14 JOB SCHEDULING (ANACRON)

We studied about cron in previous post; it is enough to take care of my scheduled jobs.

Then Why anacron…??

Let’s say your company has not paid the vendor for AMC renewal. The UPS of rack is faulty. And the state electricity board has some problem which continues to next 10 days.

Now What…?

LINUX-13 JOB SCHEDULING (AT/CRON)

LINUX-13 JOB SCHEDULING (AT/CRON)

I am not in front of system, but there is very important task which must be done now…

How it is possible…?

Either I go to office and do that, or I share my root credentials with someone whom I trust and elaborate the whole task along with each and every command.

In my opinion, these are the only ways.

LINUX-12 ACCESS CONTROL LIST (RHEL-7)

LINUX-12 ACCESS CONTROL LIST (RHEL-7)

Well, all regular/special permissions are done. Our files/directories can be secured by several ways. I have too many tools for that.

Now relaxed……

And then I announced my great knowledge everywhere, my boss also heard about my knowledge, and assigned a task where I supposed to create a script which can be run by 4 users and members of 6 groups.

Great, now I can implement my super knowledge and stun my boss with my skills.

LINUX-11 ADVANCED PERMISSIONS (RHEL-7)

LINUX-11 ADVANCED PERMISSIONS (RHEL-7)

·         Advanced permissions (SUID, SGID, STICKY BIT)

·         ID command

STICKY BIT……………………..

Let’s imagine a condition,

Where there is a shared dump directory having access of 10 users. All users are allowed to create/delete files.

That’s very ideal condition, where all are happy.

User A has 10G of movies collection.

User B has 15G of CBT’s collection.

User C has 8G of games collection.

User D has 5G of songs collection.

LINUX-10 SPECIAL ATTRIBUTES & UMASK (RHEL-7)

LINUX-10 SPECIAL ATTRIBUTES & UMASK

·         Special file attributes

·         umask

SPECIAL FILE ATTRIBUTES……………..

What we learned till now about file perms are rwx with ugo.

Beyond that “rwx” we have other perm also,

“lsattr” to view the attributes and “chattr” to change the attributes.

[root@rhel7-server user1]# su - user1

Last login: Sun Jan  1 15:57:52 IST 2017 from 192.168.234.1 on pts/0

[user1@rhel7-server ~]$ pwd

/home/user1

LINUX-9 USER ENV & SHELL (RHEL-7)

LINUX-9 USER ENV & SHELL (RHEL-7)

• ·         USER ENVIRONMENT
• ·         SHELL STARTUP FILES (SYSTEM)
• ·         SHELL STARTUP FILES (USER)
• ·         LOGIN PROMPT
• ·         LOGIN SHELLS
• ·         HOW TO SET VARIABLES

USER ENVIRONMENT…………………………………..

Whenever a user logged in to system, environment comes in picture. It’s like a room decorated according to need.

Env. Can be created as per specific user basis as well as global basis means system wide.

LINUX-8 USER LOGIN / SU

LINUX-8 USER LOGIN / SU

TERMINAL: Special-purpose physical devices which usually had a screen and a keyboard, and attached to a computer via a serial line, either directly or via a dial-up modem. Terminals were quite dumb devices, with little computation capabilities by their own: their job was mainly to display fixed-sized text coming via the serial line from the computer, and send data entered via the keyboard to the computer through the serial line, much like a teletype but with a screen in place of paper.

A device known as terminal which contains only few parts and a monitor with integrated keyboard is used to access the mainframe computer. Terminal connects with mainframe computer on serial console port. Once connected it uses all resources such as CPU, RAM and Hard disk from mainframe computer. The earliest terminals were also known as teletypes (abbreviated TTY).

LINUX-7 USER MANAGEMENT (RHEL-7)

LINUX-7 USER MANAGEMENT

User Types:     Root / Regular / Service

Root: user with administrative privilege

Regular: user level rights, can’t perform admin tasks.

Service: service user means user who take care of installed services like                    apace, ftp, mail, ntp, postfix, qemu…etc…

User account info for local users are located at…

/etc/passwd     user info

/etc/shadow     user’s password info

/etc/group      group info

/etc/gshadow    group config file