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In Linux systems, the importance of SSH cannot be underestimated. Its encrypted communication function ensures the security of data transmission, while multiple authentication methods can effectively prevent unauthorized access.
Establish secure communication links end-to-end securely to prevent data leakage.
The administrator implements flexible access control through SSH, restricting login users and IP addresses.
SSH also has auditing and logging functions, which can record user activities, allowing administrators to regularly review logs, monitor the security of the system, and detect any abnormal behavior in a timely manner.
These security features work together to ensure the overall security of the system.
/etc/ssh/sshd_config
PermitRootLogin no
sudo systemctl restart sshd
ssh-keygen
ssh-copy-id user@hostname
/etc/ssh/sshd_config
Port 22
to another portsudo systemctl restart sshd
/etc/ssh/sshd_config
AllowUsers username1 username2
sudo systemctl restart sshd
tcp_wrappers
or firewall
to configure access control/etc/ssh/sshd_config
LoginGraceTime 30s
Detect login timeoutsudo systemctl restart sshd
iptables
or ufw
/etc/ssh/sshd_config
MaxAuthTries 3
Limit the number of attemptssudo systemctl restart sshd
/etc/hosts.allow
and /etc/hosts.deny
File Configuration Access Control/var/log/auth.log
or /var/log/secure
log files to detect abnormal login behaviorBe sure to back up the configuration files before making any changes to the SSH server in case something goes wrong.
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