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Import export database | Linux

Import database

mysql -u DB_USERNAME -p DB_NAME < /PATH/OF/DB/softsql.sql

Export database

mysqldump -u DB_USERNAME -p DB_NAME > /PATH/TO/DB/softsql.sql

Dump error

  • Error Access denied need PROCESS privilege [MySQL]
  • mysqldump: Error: ‘Access denied; you need (at least one of) the PROCESS privilege(s) for this operation’ when trying to dump tablespaces

Solusion

Add ‘–no-tablespaces‘ option to the command as shown below:

mysqldump -u DB_USERNAME -p DB_NAME --no-tablespaces > /PATH/TO/DB/softsql.sql

 

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How to change the SSH port 22

How to change the SSH port

  • Log in to your server using the current SSH port (default 22).
    Note that you should not close this SSH connection until you have verified that you can access SSH on the new port number.
  • Open / etc/ssh/sshd_config
vi /etc/ssh/sshd_config
  • Set your Port. For example 1234
Port 1234
  • Restart SSHD
/scripts/restartsrv_sshd

or

sudo systemctl restart ssh.service
  • Configure any firewalls with the new SSH port.
  • Test SSH with new port 1234
ssh USER@HOSTNAME -p1234

Use your USER and HOSTNAME and the password and confirm new port.

If the SSH test on the new port is successful you can close the connection. If it is not successful, this SSH connection should not be closed until the SSH test on the new port is successful. Else revert the port to previous state and restart.

find / -name “sshd_config” -print

/usr/share/openssh/sshd_config
/etc/ssh/sshd_config

find / -name “sshd_config” 2>/dev/null

vi /usr/share/openssh/sshd_config

vi /etc/nftables.conf

ufw allow 1234/tcp

vi /etc/services

systemctl restart ssh

service ssh restart

systemctl restart ssh.service

ssh root@server_ip -p NEW_PORT
ssh root@123.512.11.6 -p 1234

 

 

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How to restrict direct root access | Linux | CentOS

We can do it just in two steps.

Step One:

At first we will create new root user as follows (for example, newroot)

  1. Login as root using SSH.
  2. Create new user e.g., newroot and add user to wheel group 
    useradd -G wheel newroot
  3. Set password for newroot 
    passwd newroot
  4. You will get option to enter password. Use letter and number only.
    Save the newroot and password somewhere of you edge.
  5. Su to newroot 
    su - newroot
  6. Test sudo permission (permission should be root) 
    sudo whoami
  7. Enter password of newroot and it will show result “root”.
  8. Open sshd config file and check whether it has the “newroot” in AllowUsers. If not, add the user manually. (usually at the end). 
    vi /etc/ssh/sshd_config

    [Permission Denied!] Quit :q

    AllowUsers newroot
  9. Restart sshd.service 
    sudo systemctl restart sshd.service

Step Two:

Now we are going to disable the root user. Before doing this, you have to logout from “root” and then login with “newroot”.

You can only disable the  “root”, if you can successfully login with “newroot”.

  1. After successfully login with “newroot”, su to “root” using root password. 
    su - root
  2. Then open sshd_config. 
    vi /etc/ssh/sshd_config
  3. Search and change permitRootLogin “yes” to “no” as follows. 
    permitRootLogin no
  4. Restart sshd.service to implement the change 
    sudo systemctl restart sshd.service
  5. Now logout from “newroot” and try to login “root”
  6. Login with root now not allowed. Access Deny.
  7. So login with “newroot” and then su to root with root password 
    su - root