Chapter 6. Using the Ubuntu Installer After selecting this new entry, you will be asked for a temporary password to be used for connecting to the installation system and for its confirmation. That’s all. Now you should see a screen which instructs you to login remotely as the user installer with the password you just provided. Another important detail to notice on this screen is the fingerprint of this system. You need to transfer the fingerprint securely to the person who will continue the installation remotely. Should you decide to continue with the installation locally, you can always press Enter , which will bring you back to the main menu, where you can select another component. Now let’s switch to the other side of the wire. As a prerequisite, you need to configure your terminal for UTF-8 encoding, because that is what the installation system uses. If you do not, remote instal- lation will be still possible, but you may encounter strange display artefacts like destroyed dialog borders or unreadable non-ascii characters. Establishing a connection with the installation system is as simple as typing: $ ssh -l installer install_host Where install_host is either the name or IP address of the computer being installed. Before the actual login the fingerprint of the remote system will be displayed and you will have to confirm that it is correct. Note: The ssh server in the installer uses a default configuration that does not send keep-alive packets. In principle, a connection to the system being installed should be kept open indefinitely. However, in some situations — depending on your local network setup — the connection may be lost after some period of inactivity. One common case where this can happen is when there is some form of Network Address Translation (NAT) somewhere between the client and the system being installed. Depending on at which point of the installation the connection was lost, you may or may not be able to resume the installation after reconnecting. You may be able to avoid the connection being dropped by adding the option -o ServerAliveInterval= value when starting the ssh connection, or by adding that option in your ssh configuration file. Note however that in some cases adding this option may also cause a connection to be dropped (for example if keep-alive packets are sent during a brief network outage, from which ssh would otherwise have recovered), so it should only be used when needed. Note: If you install several computers in turn and they happen to have the same IP address or hostname, ssh will refuse to connect to such host. The reason is that it will have different fingerprint, which is usually a sign of a spoofing attack. If you are sure this is not the case, you will need to delete the relevant line from ~/.ssh/known_hosts 11 and try again. After the login you will be presented with an initial screen where you have two possibilities called Start menu and Start shell . The former brings you to the main installer menu, where you can continue with the installation as usual. The latter starts a shell from which you can examine and possibly fix the remote system. You should only start one SSH session for the installation menu, but may start multiple sessions for shells. 11. The following command will remove an existing entry for a host: ssh-keygen -R < hostname | IP address > . 68