Boot in Single-Mode

UNIX AIX
1

Hi All,
I have AIX 5.1 & I forgot the root password. I find out the solution is to boot in single-mode and remove the root password from the /etc/passwd file. My question is how to boot in single-mode? Also is there any password required when booting in this mode?

2

AIX Guides - a place to look.

And although it isn't detailed, see Forgot root password

3

Sadly this thread is the only one I could find for AIX as was assembling the faq on this subject. If you find a detailed procedure that works, please post it here and I'll add it to the faq.

Edit:

This excellent thread has been added to the FAQ! Thanks everyone.

4

Is this any help?
Cheers
ZB

5

Sorry for late respond, thanks for all. But I noted that the AIX CD is required. Actually I don't have the CD, so is there any possible solution doesn't require the AIX CD.

6

You need physical access to the machine to do the following:

  1. switch off the machine

  2. power on and enter the SMS menu

  3. in the SMS menu there is a option called "Maintenance shell" or something such (I don't have an AIX machine at hand to try that out, but the option is named pretty intuitive).

  4. varyon rootvg, mount /

  5. edit /etc/passwd and /etc/security/passwd

  6. boot normally

bakunin

7

Thanks a lot bakunin for your response. I will try these steps & I hope to work well.

8

What do you mean by edit /etc/passwd and /etc/security/passwd?

Shane

9

Reset an Unknown Root Password
The following procedure describes how to recover access to root
privileges when the system's root password is unavailable or unknown.
The following procedure requires some system downtime. If possible,
schedule your downtime when it least impacts your workload to protect
yourself from a possible loss of data or functionality.

Insert the product media for the same version and level as the current
installation into the appropriate drive.
Power on the machine.
When the screen of icons appears, or when you hear a double beep, press
the F1 key repeatedly until the System Management Services menu appears.
Select Multiboot.
Select Install From.
Select the device that holds the product media and then select Install.
Select the AIX version icon.
Define your current system as the system console by pressing the F1 key
and then press Enter.
Select the number of your preferred language and press Enter.
Choose Start Maintenance Mode for System Recovery by typing 3 and press
Enter.
Select Access a Root Volume Group. A message displays explaining that
you will not be able to return to the Installation menus without
rebooting if you change the root volume group at this point.
Type 0 and press Enter.
Type the number of the appropriate volume group from the list and press
Enter.
Select Access this Volume Group and start a shell by typing 1 and press
Enter.
At the # (number sign) prompt, type the passwd command at the command
line prompt to reset the root password. For example:
# passwd
Changing password for "root"
root's New password:
Enter the new password again:
To write everything from the buffer to the hard disk and reboot the
system, type the following:
sync;sync;sync;reboot
When the login screen appears, the password you set in step 15 should
now permit access to root privileges.

AIX_dude

10

Thanks, AIX_dude.

Shane