What is the ubuntu 16.04 lts server default login & password?

Question

When i installed dual boot ubuntu 16.04 lts server i did not entry any ubuntu server login & password when i opened ubuntu server it wants login & password.What is the ubuntu 16.04 lts server default login & password ?or How to open ubuntu server?

Solution 1

If you don't remember the password, you can reset it with a liveCD/USB, you need to boot the USB, mount your root partition, chroot and reset the password:

# mkdir /mnt/ubuntu
# mount /dev/sdXY /mnt/ubutnu # your partition numeber
# chroot /mnt/ubuntu /bin/bash
# passwd [your username] # here you reset the password
# exit
# reboot

If You want to know your username put this command in your chroot environment:

# grep 1000 /etc/passwd

It should be the last one and the UID should be 1000 on a fresh installation if you have not a UID 1000 means you have not created a username, so add it, always on your chroot environment:

# uaseradd -s /bin/bash -G users,wheel,... [your username]
# passwd [your username]

Solution 2

With Ubuntu, you do not need to boot a live CD (and chroot) as you should be able to use the ... (recovery mode) option in the grub menus.

To see the grub menu; hold SHIFT as the BIOS ends it's boot-up display.

Select the recovery mode with the cursor keys (then press ENTER) and a new menu appears.

Select and press enter on
fsck Check all file systems
to make all filesystems writable.

Select and press enter on
network Enable networking
... if also need networking (e.g. to run apt-get)

Select and press enter on
root Drop to root shell prompt
... and ENTER once more, to get the root shell prompt.

Now use useradd, usermod, userdel and passwd in the normal way to reset password(s) or create/modify/remove users.

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Note also: ALL answers here should be considered "$3cur1ty h0l3z" - anybody with physical access to the machine can do this; root access without effort. So, what to do? -> Keep your computer in a locked room.

Comments

[Kamil Maciorowski]

Note: not every liveCD/USB will work: (1) the implicit premise is it contains Linux; (2) chroot will use the kernel of this live OS, version mismatch may be an issue in general (although the mentioned commands should not be picky, I guess).

[ensarman]

first... thanks, about the editing... my english is not perfect :P second... It is true, Its recommended to use the same liveCD/USB used to install the SO

[Hannu]

Even with use of the actual install media you may have a mismatch, e.g. if there has been updates that included changes to system portions that affects what you're about to handle.