The software described in this documentation is either in Extended Support or Sustaining Support. See https://www.oracle.com/us/support/library/enterprise-linux-support-policies-069172.pdf for more information.
Oracle recommends that you upgrade the software described by this documentation as soon as possible.
The Secure Shell (SSH) allows protected, encrypted communication
with other systems. As SSH is an entry point into the system,
disable it if it is not required, or alternatively, edit the
/etc/ssh/sshd_config
file to restrict its
use.
For example, the following setting does not allow
root
to log in using SSH:
PermitRootLogin no
You can restrict remote access to certain users and groups by
specifying the AllowUsers
,
AllowGroups
, DenyUsers
,
and DenyGroups
settings, for example:
DenyUsers carol dan AllowUsers alice bob
The ClientAliveInterval
and
ClientAliveCountMax
settings cause the SSH
client to time out automatically after a period of inactivity,
for example:
# Disconnect client after 300 seconds of inactivity ClientAliveCountMax 0 ClientAliveInterval 300
After making changes to the configuration file, restart the
sshd
service for your changes to take effect.
For more information, see the sshd_config(5)
manual page.