SSH Passwordless or RSA key authentication

Log to a remote system using SSH without having to type the password.
This has few different names, such as: passwordless, RSA key authentication, key based auth etc.

Recently i was trying to implement a mechanism to save all logs under /var/log/ to a central server, just for keeping a record daily of these logs, in case we need to check things out at later date (security).

You will need to make some changes to the remote SSH server and the local SSH client.
To start with lets name two Linux Servers: Linux01 and Linux02.

You want to lot to Linux02 from Linux01 without having to type the password for a specific user, let's call it "user01".

Make sure the user exists on both Linux servers or at least on the remote Server (Linux02).
# adduser user01
# passwd user01

# su - user01
~ ssh-keygen

cat .ssh/id_rsa.pub | ssh user01@linux02 'cat >> .ssh/authorized_keys'

chmod 600 authorized_keys

by Renato de Oliveira

Send Users Commands typed in the SHELL to Syslog

# cd /etc

# vi profile

Add the lines below:
function history_to_syslog
{
        declare command
        command=$(fc -ln -0)
        if [ "$command" != "$old_command" ]; then
                logger -p local1.notice -t bash -i -- $USER : "$command"
        fi
        old_command=$command
}
trap history_to_syslog DEBUG


# vi rsyslog.conf

Add the lines below:
# Logging users BASH commands to syslog
local1.notice                                           /var/log/cmd.log

By Renato

Juniper SRX web-management not loading or working (Security)

Today I was trying to do some work on one of our Juniper Firewalls and I tried and tried to access the web interface and no luck.
I could access the firewall over SSH but I wanted to visually check the configuration using HTTP.

I tried resetting logs
I tried removing old traceoptions
I did not want to reboot the firewall and I did not! Happy days

In the end what did the trick was easy option, to restart the web-management

admin@firewall> edit
admin@firewall# run restart web-management
Web management gatekeeper process started, pid 75995

{primary:node0}[edit]
admin@ccpsrx240-01#

And that is it!

If you come across this problem next time.

by Renato de Oliveira

Give root privileges without giving root shell (Security)

Give root privileges without giving root shell

If you have a team of Linux Sysadmins, and would like the team to have root privileges, but would not want to give a shell to them, this is what you need to do.

You will need to familiarise yourself with a package called sudo. Let's say you have a sysadmin named admin1.
All you need to do is:
Create an account for admin1 then edit the sudo configuration file called sudoers.

Create new user
# adduser admin1

Set the new users password
# passwd admin1

Change to etc folder
# cd /etc

Edit sudo config file
# vi sudoers
 Add the lines below to sudoers

## Shell and SU
Cmnd_Alias      NSHELLS  =       /bin/sh,/bin/bash
Cmnd_Alias      NSU            =       /bin/su

admin1  ALL=(ALL)       ALL
It is that simple. Does not take too long and now you can keep the root password separate and do not need to disclose it to other sys admins.

by Renato de Oliveira

Rushing Around by Renato de Oliveira

Rushing around
Trying to do everything
There is a feeling
Something I am missing

So many hours in a day
How many things can I do?
Even if I don't sleep
I can't do much too

Rushing around
This is how I am feeling
Never enough time
For what I need

From one thing to another
Jumping from here to there
Why should I even bother
Or even really care

Frustration builds up
Never finishing what I started
goal post is a moving target

Rushing around
is the new world we live in
There is never enough time
for you or for me

I like writing and I am exercising my writing in English. If you like this lyric and would like to make a song just get in touch.

My Days Are Counted

My Days Are Counted by Renato de Oliveira

I have this feeling

What’s the meaning of all of that

Is it really worth it

I go home, what do I have

My days are counted

How many I don’t know

My days are counted

I just have to go

I just have this feeling

And it won’t go away

It is so unfulfilling

I just can’t stay

My days are counted

1, 2 , 3 I really don’t know

My days are counted

I just have to go

It is not that easy

To live this way

A life without meaning

Dragging day by day.

Counting my days

How far can I go?

Counting my days

It is sad though

My days are counted…..

If you find this lyric interesting or good and are interested in making a song of it, just get in touch and I have some ideas.

by Renato de Oliveira

Crete Partitions larger than 2TB

Crete Partitions larger than 2TB

Create a partition on Linux using parted and labelling it with gpt

1.dmesage |grep sd

2.parted /dev/sdb
3.(parted) mklabel gpt
4.(parted) unit TB
5.(parted) mkpart primary 0.00 4.95TB
6.(parted) print
7.(parted) quit
8.mkfs.ext4 /dev/sdb1

9.vi /etc/fstab (add)
   /dev/sdb1 /local ext4 defaults 1 2

 

Add New Volume

1. Added physical disks

2. Created RAID 1 Volume
3. umount /local/
5. # vgdisplay
6. dmesg | grep sd

      sd 0:0:0:2: [sdb] 1172058032 512-byte logical blocks: (600 GB/558 GiB)

7. # pvcreate /dev/sdb
8. # pvdisplay – check if it has been created
 
"/dev/sdb" is a new physical volume of "558.88 GiB"
  --- NEW Physical volume ---
  PV Name               /dev/sdb
  VG Name
  PV Size               558.88 GiB
  Allocatable           NO
  PE Size               0
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               SX1ekz-o4Aj-5yXO-QbIF-AdPw-L3Iq-kewNFQ

9. find out the existing name for the existing volume group: 

# vg_local

# vgdisplay

 10. vgcreate vg_local600 /dev/sdb

 

11. check if group has been created:

#  vgdisplay | grep 600
12. lvcreate -L 550G -n lv0_local600 vg_local600

 

13. Find the File system type:

# cat /etc/fstab | grep ext = ext4

 14. Create file system

mkfs.ext4 /dev/vg_local600/lv0_local600

15. # mount new file system

mount /dev/vg_local600/lv0_local600 /local