Tag: users

Update sshd configuration

AT Deny an ssh user login, add this to the end of your sshd configuration file (/etc/ssh/sshd_config under Linux / Unix / BSD):

DenyUsers theusername

For groups:

DenyGroups thegroupname

Restart the sshd service

Then restart sshd a service. The following works on Ubuntu 18.04:

systemctl restart sshd

More details

We can add a space-separated list of user or group names, respectively.

the AllowUsers and AllowGroups directives do the opposite.

From the sshd_config manual page:

DenyGroups

This keyword can be followed by a group name list
patterns, separated by spaces. Connection is prohibited to users whose
the main group or list of additional groups corresponds to one of the models.
Only group names are valid; a digital group ID is not recognized. By
by default, connection is allowed for all groups. The allow / deny directives
are processed in the following order: DenyUsers, AllowUsers,
DenyGroups, and finally AllowGroups.

DenyUsers

This keyword can be followed by a list of usernames
patterns, separated by spaces. Login is not allowed for usernames that
match any of the patterns. Only usernames are valid; a digital user
The ID is not recognized. By default, connection is allowed for all users. Yes
the pattern takes the form USER @ HOST then USER and HOST are separately
checked, restricting connections to particular users from particular hosts.
The allow / deny directives are processed in the following order:
DenyUsers, AllowUsers, DenyGroups, and finally AllowGroups.

See REASONS in ssh_config (5) for more information on the models.