By default, ubuntu root can change the initial password, logout, and IP address.

After Ubuntu is installed, the root user does not have the default password, because you have not set the password for the root user. Your first user is in the admin group and can set the password for the root user, so you don't have to worry about the number of your own passwords, because they don't exist at all.

Enter the following command on the Port:

Sudo passwd root
[Sudo] password for you: ---> enter your password and do not echo
Enter new UNIX password: ---> set the root password
Retype new UNIX password: --> repeated

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The logout command after entering X

Gnome Environment: gnome-session-save -- logout
Opebox environment: openbox -- exit

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Modify the IP address of ubuntu

Temporarily modify IP Address:
Sudo ifconfig eth0 192.168.X.X netmask 255.255.255.0 up

Permanent IP address modification:
Sudo vim/etc/network/interface

Auto lo
Iface lo inet loopback
Auto eth0
Iface eth0 inet static
Hwaddress ether XX: XX (here is the MAC address to be set)
Address 192.168.X.X (the IP address to be set here)
Netmask 255.255.255.0
Gateway 192.168.X.X (the gateway to be set here)

Then restart the Network Configuration:
Sudo/etc/init. d/networking restart

OK!