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su: Authentication failure. sudo works but su doesn't

asked 2019-04-25 16:53:43 -0500

The su command doesn't seem to be working on my fresh Fedora 29 installation. It asks for a password and then it just says: su: Authentication failure.

The password is the correct one, I use the same with sudo and works fine. Help!

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sudo takes your USERPASSWORD, su needs the ROOTPASSWORD.. two different passwords and since F29 does not set a root password on installation, you will never now it until you set it explicitly.

rdtcustomercare gravatar imagerdtcustomercare ( 2019-04-26 02:42:43 -0500 )edit

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answered 2019-04-25 21:40:54 -0500

florian gravatar image

su requires you to provide root’s password. On Fedora 29 you first need to set up a root password.

You can use

sudo su -

and then


(sudo passwd should work as well)

When you use the sudo command, you will be asked for your user’s password!

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answered 2019-04-26 00:50:47 -0500

sulthan90 gravatar image

I used these steps and this solved the same problem for me

  1. Open Terminal and type sudo passwd root
  2. Now terminal will ask for your password type your existing password
  3. After you entered your correct password. Now the terminal will ask for new password. This will be used as a root password. You can keep this password the same as Sudo password.
  4. Re-enter the password to confirm. After this, you will be able to use root access in the terminal.

Let me know if this worked for you.

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Asked: 2019-04-25 16:53:43 -0500

Seen: 27,935 times

Last updated: Apr 26 '19