PermitRootLogin, in /etc/ssh/sshd_config (that one can edit with 'sudo pluma
/etc/ssh/sshd_config'), specifies whether root can log in using ssh. 'man
sshd_config' explains:
PermitRootLogin
Specifies whether root can log in using ssh(1). The argument
must be “yes”, “prohibit-password”, “without-password”,
“forced-commands-only”, or “no”. The default is
“prohibit-password”.
If this option is set to “prohibit-password” or
“without-password”, password and keyboard-interactive authentication are
disabled for root.
If this option is set to “forced-commands-only”, root login
with public key authentication will be allowed, but only if the command
option has been specified (which may be useful for taking remote backups even
if root login is normally not allowed). All other authentication methods are
disabled for root.
If this option is set to “no”, root is not allowed to log
in.
By default, Trisquel does not have a root user. As a consequence, it cannot
log in, even locally.
